MCS3122_技术文档

MCS3122

®

MCS3122 Advanced KEE

L

OQ Technology Encoder Data Sheet

Features Overview

Typical Applications

• Advanced KEELOQ^®Technology:

- Programmable 32-bit serial number

MCS3122 is ideal for Remote Keyless Entry (RKE)

applications. These applications include:

- Programmable 32-bit serial number for seed

transmissions

- AES-128 block cipher

- Programmable 128-bit crypt key

- 160/192-bit transmission code length:

- 32-bit unencrypted portion

- 128-bit encrypted, code hopping portion

- 32-bit authorization check (optional)

• Operating Features:

• Automotive RKE Systems

• Automotive Alarm Systems

• Gate and Garage Door Openers

• Home Security Systems

• Security and Safety Sensors

• Remote Control

• Remote Keypad

• Wireless Sensors

- 2.0 to 3.7V operation

- Three switch inputs

Package Type

- Seven functions available

- One active-low LED drive

- Configurable maximum code word

• RF:

• 14-Pin TSSOP

FIGURE 1:

14-PIN TSSOP

- Configurable bit rate

- Configurable modulation, supporting FSK

and OOK

- Configurable data modulation, supporting

PWM and Manchester

• Other:

14

13

12

11

10

9

VSS

SW0

SW1

DATA_OUT

XTAL

VDD

LED

CTRL_OUT

SW2

VDD

CTRL_IN

RFOUT

1

2

3

4

5

6

7

DATA_IN

VSS

- Button inputs have internal pull-up resistors

8

TABLE 1:

Name

PIN DESCRIPTION

14-Pin TSSOP

Input Type

Output Type

Description

VDD

1

2

Power

—

TTL

—

Power

LED

LED Output (active-low)

Transmitter Clock

Switch 2 Input

CTRL_OUT

SW2

3

—

4

TTL

VDD

5

Power

TTL

—

Power

CTRL_IN

RFOUT

VSS

6

—

Transmitter Clock

Transmitter Output

Power

7

—

RF

—

8

Power

TTL

DATA_IN

XTAL

9

—

Transmitter Data

Transmitter Reference Oscillator

Transmitter Data

Switch 1 Input

10

11

12

13

14

Analog

—

DATA_OUT

SW1

TTL

—

TTL

SW0

TTL

—

Switch 0 Input

VSS

Power

—

Power

 2014 Microchip Technology Inc.

DS40001762A-page 1

MCS3122

Table of Contents

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

General Description ................................................................................................................................................................... 3

Device Description .................................................................................................................................................................... 4

Memory Organization................................................................................................................................................................. 5

®

Advanced KEELOQ Technology Operation............................................................................................................................... 9

Transmitter Operation.............................................................................................................................................................. 12

Integrating MCS3122 into a System ........................................................................................................................................ 15

Electrical Specifications ........................................................................................................................................................... 17

Packaging Information ............................................................................................................................................................. 18

The Microchip Web Site....................................................................................................................................................................... 23

Customer Change Notification Service ................................................................................................................................................ 23

Customer Support................................................................................................................................................................................ 23

Product Identification System .............................................................................................................................................................. 24

TO OUR VALUED CUSTOMERS

It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip

products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and

enhanced as new volumes and updates are introduced.

If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via

E-mail at docerrors@microchip.com. We welcome your feedback.

Most Current Data Sheet

To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:

http://www.microchip.com

You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.

The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000).

Errata

An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current

devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision

of silicon and revision of document to which it applies.

To determine if an errata sheet exists for a particular device, please check with one of the following:

•

Microchip’s Worldwide Web site; http://www.microchip.com

Your local Microchip sales office (see last page)

When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are

using.

Customer Notification System

Register on our web site at www.microchip.com to receive the most current information on all of our products.

DS40001762A-page 2

 2014 Microchip Technology Inc.

MCS3122

• Decryption Algorithm: A recipe whereby data,

scrambled by an encryption algorithm, can be

unscrambled using the same crypt key.

1.0

GENERAL DESCRIPTION

MCS3122 is a KEELOQ encoder, designed for secure

Remote Keyless Entry (RKE) and secure remote

control systems. MCS3122 utilizes the Advanced

KEELOQ code hopping technology. The encoder

incorporates a high- security, low-cost small package

outline to make this device the perfect solution for

unidirectional authentication systems and access

control systems.

• Learn: Learning involves the receiver calculating

the transmitter’s appropriate crypt key, decrypting

the received hopping code and storing the serial

number, synchronization counter or timer value,

and crypt key in EEPROM. The KEELOQ

technology product family facilitates several

learning strategies to be implemented on the

decoder. The following are examples of what can

be done:

The Advanced KEELOQ technology uses the industry

standard AES-128 encryption algorithm, a serial

number and a message counter which continuously

increments with each button press.

- Simple Learning: The receiver uses a fixed

crypt key. The crypt key is common to every

component used by the same manufacturer.

The crypt key, serial number and configuration data are

stored in a Flash array which is not accessible via any

external connection. The Flash data is programmable

but read-protected. The data can be verifiedonlyafter

an automatic erase and programming operation. This

protects against attempts to gain access to keys or

manipulate synchronization values. In addition,

MCS3122 provides an easy to use serial interface for

programming the necessary keys, system parameters

and configuration data.

- Normal Learning: The receiver derives a

crypt key from the encoder serial number.

Every transmitter has a unique crypt key.

- Secure Learning: The receiver derives a

crypt key from the encoder seed value. Every

encoder has a unique seed value that is only

transmitted by a special button combination.

• Manufacturer’s Code: A unique and secret

number

(128-bit

for

Advanced

KEELOQ

technology) used to derive crypt keys. Each

encoder is programmed with a crypt key that is a

function of the manufacturer’s code. Each

decoder is programmed with the manufacturer’s

code itself.

1.1

Key Terms

The following is a list of key terms used throughout this

data sheet. For additional information on KEELOQ

technology and code hopping, refer to “An Introduction

to KEELOQ^®Code Hopping” Technical Brief (DS91002).

The MCS3122 code hopping encoder is designed

specifically for keyless entry systems. Typical

applications include vehicles and home garage door

openers. The encoder portion of a keyless entry system

is integrated into a transmitter carried by the user. The

transmitter is operated to gain access to a vehicle or a

restricted area. MCS3122 is meant to be a cost-

effective, yet secure solution to such systems, requiring

very few external components (see Figure 2-1).

• RKE: Remote Keyless Entry

• Function Code: It indicates what button input(s)

activated the transmission. It encompasses the

function code bits.

• Code Hopping: A method by which a code,

viewed externally to the system, appears to

change unpredictably each time it is transmitted.

• Code Word: A block of data that is repeatedly

transmitted upon button activation.

Most low-end keyless entry transmitters are given a

fixed identification code that is transmitted every time a

button is pushed. The number of unique identification

codes in a low-end system is usually a relatively small

number. These shortcomings provide an opportunity

for a sophisticated thief to create a device that ‘grabs’

a transmission and retransmits it later, or a device that

quickly ‘scans’ all possible identification codes until the

correct one is found.

• Transmission: A data stream consisting of

repeating code words.

• Crypt Key: A unique and secret number (128-bit

for Advanced KEELOQ technology) used to

encrypt and decrypt data. In a symmetrical block

cipher such as those used on MCS3122, the

encryption and decryption keys are equal and,

therefore, will generally be referred to as the crypt

key.

Advanced KEELOQ technology uses the industry

standard AES-128 encryption algorithm to obscure

data using 128 bits for both its block and key length. In

addition to the security of Advanced KEELOQ

• Encoder: A device that generates and encodes

data.

• Encryption Algorithm: A method whereby data

is scrambled using a crypt key. The data can only

be interpreted by the respective decryption

algorithm using the same crypt key.

technology, the encoder sends

authorization block which is used to separate the

message encryption from the message authentication.

a

message

• Decoder: A device that decodes data received

from an encoder.

 2014 Microchip Technology Inc.

DS40001762A-page 3

MCS3122

2.0

DEVICE DESCRIPTION

As shown in the typical application circuit (Figure 2-1),

MCS3122 is a simple device to use. It requires only the

addition of up to three buttons, a transmitter reference

oscillator, and RF circuitry for use as the transmitter in

the security application. See Table 1 for a description of

each pin.

FIGURE 2-1:

TYPICAL CIRCUIT

VDD

LED

VSS

SW0

LED

B0

B1

SW1

CTRL_OUT

DATA_OUT

XTAL

SW2

B2

VDD

CTRL_IN

DATA_IN

VSS

XTAL

Matching

Circuit

Block

RFOUT

DS40001762A-page 4

 2014 Microchip Technology Inc.

MCS3122

3.0

MEMORY ORGANIZATION

MCS3122 has 64 bytes of configuration data. In

general, the Configuration bytes can be divided into

two categories: those options related to the Advanced

KEELOQ technology encoder and those related to the

transmitter and device operation.

TABLE 3-1:

Address

CONFIGURATION REGISTERS

Size (Bytes)

Description

0x00-0x02

0x03

3

1

Synchronization Counter, Copy A

Synchronization Counter Checksum

0x04-0x07

0x08-0x0A

0x0B

4

Reserved (set to 0xFF)

3

Synchronization Counter, Copy B

Reserved (set to 0xFF)

1

0x0C-0x0F

0x10-0x1F

0x20-0x2F

0x30-0x33

0x34-0x35

0x36-0x37

0x38-0x3F

4

Seed Transmission Serial Number (usually set to 0xFFFFFFFF)

16

4

Encryption Key

Authorization Key

Serial Number

2

Transmitter Settings

Reserved (set to 0xFF)

Seed Value

2

8

3.1

Counter and Protection

The synchronization counter is read, checked for

integrity, updated (incremented) and saved back to

Flash during normal operation of the device. The

special operation prevents against data loss from

unexpected power loss. An 8-bit checksum is

calculated and stored alongside the synchronization

counter. The checksum is calculated as a two’s

complement checksum. If there is a mismatch, the

second copy of the synchronization counter is read

instead. Example 3-1 illustrates how to compute this

value.

EXAMPLE 3-1:

CHECKSUM CALCULATION

static uint8_t crc(const uint8_t* buffer, size_t len){

uint8_t bitcount;

uint8_t checksum = 0xFF;

while(len--)

{

c = c + *buffer++;

}

return 0-c;

}

 2014 Microchip Technology Inc.

DS40001762A-page 5

MCS3122

3.2

Configuration Byte Details

The following tables describe Configuration bytes in

detail.

TABLE 3-2:

Byte Address

ADVANCED KEELOQ^®TECHNOLOGY SYNCHRONIZATION REGISTERS, COPY A

Bit

Description

Values

0x00

0x01

0x02

0x03

7:0 Synchronization

Byte 0 of the synchronization counter (LSB)

Byte 1 of the synchronization counter

Counter, Copy A

7:0

Byte 2 of the synchronization counter (MSB)

Checksum of the synchronization counter

7:0 Checksum

TABLE 3-3:

ADVANCED KEELOQ^®TECHNOLOGY SYNCHRONIZATION REGISTERS, COPY B

Byte Address

Bit

Description

Values

0x08

0x09

0x0A

7:0 Synchronization

Byte 0 of the synchronization counter (LSB)

Byte 1 of the synchronization counter

Counter, Copy B

7:0

Byte 2 of the synchronization counter (MSB)

TABLE 3-4:

ADVANCED KEELOQ^®TECHNOLOGY SEED SERIAL NUMBER REGISTERS

Bit Description Values

7:0 Seed Serial Number Byte 0 of the seed serial number (LSB)

Byte Address

0x0C

0x0D

0x0E

0x0F

7:0

Byte 1 of the seed serial number

Byte 2 of the seed serial number

Byte 3 of the seed serial number (MSB)

TABLE 3-5:

ADVANCED KEELOQ^®TECHNOLOGY CRYPT KEY REGISTERS

Byte Address

Bit

Description

Crypt Key

Values

Byte 0 of the crypt key (LSB)

0x10

0x11

0x12

0x13

0x14

0x15

0x16

0x17

0x18

0x19

0x1A

0x1B

0x1C

0x1D

0x1E

0x1F

7:0

Byte 1 of the crypt key

Byte 2 of the crypt key

Byte 3 of the crypt key

Byte 4 of the crypt key

Byte 5 of the crypt key

Byte 6 of the crypt key

Byte 7 of the crypt key

Byte 8 of the crypt key

Byte 9 of the crypt key

Byte 10 of the crypt key

Byte 11 of the crypt key

Byte 12 of the crypt key

Byte 13 of the crypt key

Byte 14 of the crypt key

Byte 15 of the crypt key (MSB)

DS40001762A-page 6

 2014 Microchip Technology Inc.

MCS3122

TABLE 3-6:

Byte Address

ADVANCED KEELOQ^®TECHNOLOGY AUTHORIZATION KEY REGISTERS

Bit

Description

Values

0x20

0x21

0x22

0x23

0x24

0x25

0x26

0x27

0x28

0x29

0x2A

0x2B

0x2C

0x2D

0x2E

0x2F

7:0

Authorization Key

Byte 0 of the authorization key (LSB)

Byte 1 of the authorization key

Byte 2 of the authorization key

Byte 3 of the authorization key

Byte 4 of the authorization key

Byte 5 of the authorization key

Byte 6 of the authorization key

Byte 7 of the authorization key

Byte 8 of the authorization key

Byte 9 of the authorization key

Byte 10 of the authorization key

Byte 11 of the authorization key

Byte 12 of the authorization key

Byte 13 of the authorization key

Byte 14 of the authorization key

Byte 15 of the authorization key (MSB)

TABLE 3-7:

ADVANCED KEELOQ^®TECHNOLOGY SERIAL NUMBER REGISTERS

Byte Address

Bit

Description

Values

0x30

0x31

0x32

0x33

7:0

Serial Number

Byte 0 of the serial number (LSB)

Byte 1 of the serial number

Byte 2 of the serial number

Byte 3 of the serial number (MSB)

 2014 Microchip Technology Inc.

DS40001762A-page 7

MCS3122

TABLE 3-8:

Byte Address

0x34

TRANSMITTER CONFIGURATION REGISTERS

Bit Description

Values

7:6 FSK Frequency Deviation 11– 200 kHz

10– 100 kHz

01– 75 kHz

10– 50 kHz

5

4

3

Output Power

Encoding

0– 0 dBm

1– 10 dBm

1– PWM

0– Manchester

Modulation

1– OOK

0– FSK

2:0 Frequency Select

000– 315.00 MHz (only with 24 MHz crystal)

001– 390.00 MHz

010– 418.00 MHz

011– 433.92 MHz

100– 868.30 MHz

101– 868.65 MHz

110– 868.95 MHz

111– 915.00 MHz

0x35

3

Seed Button Configuration 111– Disabled, no seed option

and

1:0

110– SW0

101– SW1

100– SW1 and SW0

011– SW2

010– SW2 and SW0

001– SW2 and SW1

000– SW3, SW2 and SW1

2

Authorization Code Enable 1– Enabled

0– Disabled

5:4 Baud Rate

11– 200 µS

10– 150 µS

11– 100 µS

11– 50 µS

7:6 Maximum Code Words

11– 234 words

10– 80 words

01– 4 words

00– No maximum limit

TABLE 3-9:

Byte Address

ADVANCED KEELOQ^®TECHNOLOGY SEED CONFIGURATION REGISTERS

Bit Description Values

Byte 0 of the seed value (LSB)

0x38

0x39

0x3A

0x3B

0x3C

0x3D

0x3E

0x3F

7:0 Seed Value

7:0

Byte 1 of the seed value

Byte 2 of the seed value

Byte 3 of the seed value

Byte 4 of the seed value

Byte 5 of the seed value

Byte 6 of the seed value

Byte 7 of the seed value (MSB)

DS40001762A-page 8

 2014 Microchip Technology Inc.

MCS3122

®

4.0

4.1

ADVANCED KEELOQ

TECHNOLOGY OPERATION

Synchronization Counter

This is the 24-bit synchronization value that is used to

create the hopping code for transmission. This value

will be incremented after every transmission. The initial

value of the synchronization counter may be set via the

Synchronization Counter Initial Value registers (see

Table 3-2 and Table 3-3).

4.2

Function Code (Button Status

Code)

The function code is a bitmapped representation of the

state of each button on the transmitter. States are

active-high.

®

TABLE 4-1:

ADVANCED KEELOQ

BUTTON CODE

TRANSLATION

Button

Function Code

SW0

SW1

SW2

xx1

x1x

1xx

4.3

Serial Number

Each Advanced KEELOQ encoder transmits its 32-bit

serial number with each transmission. It is intended

that this serial number be unique to a system. It is set

in the Serial Number Configuration registers, listed in

Table 3-7.

4.4

Seed Code Serial Number

The transmitter has the possibility to set the serial

number which will be transmitted with a seed

transmission. In a typical system, this serial number is

transmitted as 0xFFFFFFFF; however, the user can

configure this according to the actual application. The

seed code serial number is set in the Seed Code

Configuration registers, listed in Table 3-4.

 2014 Microchip Technology Inc.

DS40001762A-page 9

MCS3122

4.5

Code Word Format

The Advanced KEELOQ code word is either 160 or

192-bit long. It comprises three sections (see Figure 4-1):

• 32 Bits of the Encoder’s Serial Number

• 128 Bits of the Encrypted Hopping Code

• 32 Bits of the Authorization Code (optional)

These segments are described in detail in the following

sections.

FIGURE 4-1:

ADVANCED KEELOQ^®CODE WORD FORMAT

32 bits

128 bits Encrypted Hopping Code

Function

Fixed Portion

Auth Portion

Sync.

Authorization

Code

Serial Number 0x55AA55

0x55

0xAA55AA55 0xAA55

0xAA55

16-bits

Counter

Code

32-bits

Note:

24-bits

8-bits

32-bits

16-bits

32-bits

The data is sent LSB first (in this figure from right to left).

4.5.1

FIXED CODE PORTION

FIGURE 4-2:

AUTHORIZATION CODE

CALCULATION

The fixed code portion consists of 32 bits of the serial

number.

Encrypted

Code Word

Serial

Number

4.5.2

HOPPING CODE PORTION

The hopping code portion is calculated by encrypting

the synchronization counter and function code with the

encoder key. The hopping code is calculated when a

button press is registered.

0

4.5.3

AUTHORIZATION CODE PORTION

Authorization

Key

Authorization

Code

E

The authorization code is a cryptographically-strong

industry standard representation of the code word

suitable for authentication and integrity verification. It is

generated by using the on-board AES encryption

algorithm in CBC-MAC mode. The calculation takes

place over the entire code word, including the

encrypted and unencrypted portions, using the

The authorization code portion consists of the 32-bit Least

Significant bits of the authorization code.

authorization key as input. Figure 4-2 shows

a

representation of how this calculation is performed.

This calculation is truncated to its Least Significant 32

bits for transmission.

The authorization code requires a shared secret called

the authorization key. This key is set in the

Authorization Key Configuration register, listed in

Table 3-6.

DS40001762A-page 10

 2014 Microchip Technology Inc.

MCS3122

4.5.4

SEED WORD FORMAT

The seed word is used when pairing the transmitter to

a receiver using a secure learn methodology. The seed

code word format is shown is Figure 4-3. While the

MCS3122 Flash data contains user-configurable 64-bit

seed data, the encoder will send 128-bit seed code.

The 128-bit seed code is constructed using the

user-configured seed code for the lower 64 bits of the

seed. The upper 64 bits are added by MCS3122 as 8

bytes with a 0x12 value.

FIGURE 4-3:

ADVANCED KEELOQ^®SEED WORD FORMAT⁽¹⁾

32 bits

Fixed Portion

32 bits

Auth. Portion

128 bit Seed

Authorization

Code

Serial Number

64-Bit Padded Seed Upper Value⁽²⁾

64-Bit Configurable Seed Lower Value

Note 1: MCS3122 can set a different serial number for the seed packet. This is typically set to 0xFFFFFFFF.

2: The padded value is 0x1212121212121212.

3: The data is sent LSB first (in this figure from right to left.

 2014 Microchip Technology Inc.

DS40001762A-page 11

MCS3122

5.0

5.1

TRANSMITTER OPERATION

Data Modulation Format and Baud

Rate

A transmission is made up of several code words. Each

code word contains a preamble, header and data. A

code word is separated from another code word by

guard time.

All timing specifications for the modulation formats are

based on a basic Time Element, described as TE. See

Section 5.2 “Baud Rate” for details on baud rate

calculation. This timing element can be set to a wide

range of values. The length of the preamble, header

and guard is fixed. The guard time is fixed to a typical

18.5 ms.

FIGURE 5-1:

PWM TRANSMISSION FORMAT

TE TE

TE

Logic ‘0’

Logic ‘1’

TBP

1

16

10 TE

31 TE Preamble

Guard

Time

Encrypted Portion

Fixed Code Portion

Header

FIGURE 5-2:

MANCHESTER TRANSMISSION FORMAT

TE

Logic ‘0’

Logic ‘1’

TBP

Start bit

16

bit 0 bit 1 bit 2

Stop bit

1

2

10 TE

Header

Guard

Time

Preamble

Encrypted Portion

Fixed Code Portion

DS40001762A-page 12

 2014 Microchip Technology Inc.

MCS3122

5.2

Baud Rate

5.5

Deviation Selection

The baud rate of an encoder’s transmission is highly

configurable using the two bits in the Transmitter

Setting Byte 1 register (0x35).

When using FSK modulation, the frequency deviation

can be configured using bits <7:6> in the Transmitter

Settings Byte 0 register (0x34).

TABLE 5-4:

FREQUENCY DEVIATION

SELECTION OPTIONS

TABLE 5-1:

BAUD RATE SELECTION

OPTIONS

Deviation

200 kHz

Bits <7:6>

TE (µS)

Bits <5:4>

11

10

01

00

200

150

100

50

1:1

1:4

100 kHz

75 kHz

50 kHz

1:4

1:16

5.6

Power Output

5.3

Transmission Modulation Format

The RF output power can be configured to either 0 dBm

or 10 dBm. The setting is done using bit <5> in the

Transmitter Settings Byte 0 register (0x34).

The RF transmission can be configured to modulate

using Frequency-Shift Keying (FSK) or On-Off Keying

(OOK). The selection is done using one bit in the

Transmitter Settings Byte 0 register (0x34).

TABLE 5-5:

OUTPUT POWER SELECTION

OPTIONS

TABLE 5-2:

MODULATION FORMAT

SELECTION OPTIONS

Out Power

0 dBm

10 dBm

Bit <5>

0

1

Modulation

FSK

OOK

Bit <3>

0

1

5.4

Frequency and Band Selection

The RF frequency configuration is performed by

selecting the appropriate bits in the Transmitter

Settings Byte 0 register (0x34).

TABLE 5-3:

FREQUENCY SELECTION

OPTIONS

Frequency

315.00 MHz⁽¹⁾

Bits <2:0>

000

001

010

011

100

101

110

111

390.00 MHz

418.00 MHz

433.92 MHz

868.30 MHz

868.65 MHz

868.90 MHz

915.00 MHz

Note 1: For 315.00 MHz operation, a 24 MHz

crystal is required. All the other frequency

settings will require a 26 MHz crystal.

 2014 Microchip Technology Inc.

DS40001762A-page 13

MCS3122

5.7

Crystal Selection

Once the frequency band has been selected, the choice

of crystal frequency is flexible provided the crystal

meets the specifications summarized in Table 5-6, the

boundaries of the Encoder Frequency Configuration

value are followed and the RF transmit frequency error

is acceptable to the system design.

TABLE 5-6:

Symbol

CRYSTAL RESONATOR SPECIFICATIONS

Description

Crystal Frequency

Min.

Typ.

Max.

Unit

f_REF

CL

—

26 or 24⁽¹⁾

—

MHz

pF

Load Capacitance

15

—

ESR

Equivalent Series Resistance

100

Ω

Note 1: When selecting the 315.000 MHz frequency, a 24 MHz crystal is required.

5.8

Seed Button Configuration

5.10 Maximum Code Words

The MCS3122 allows the user to select which button

combination will output the seed transmission instead

of the normal data packet. Table 5-7 lists all the

possible button combinations.

This feature sets a maximum number of code words

transmitted by a button configuration. If a button is kept

pressed, the maximum allowed code words will be

transmitted. If a new button is pressed or a new button

press combination is used, the process will be restarted

and the maximum number of words will be transmitted.

TABLE 5-7:

SEED BUTTON

CONFIGURATION OPTIONS

Bit Settings

SW2

SW1

SW0

<3> and

<1:0>

Closed

Open

Closed

Open

000

001

Closed

Open

Closed

Open

010

Open

011

Closed

Open

Closed

Open

100

Open

101

Open

Closed

Open

110

111⁽¹⁾

Open

Note 1: The button combination corresponding to

the setting ‘111’ will not generate a seed

combination since it corresponds to all

buttons not pressed. Setting the bits to

this value will disable the seed packet

sending (i.e., no button combination will

send a seed code).

5.9

Code Word Completion

MCS3122 always ensures that a full and complete

code word is transmitted even if all buttons are

released before transmission is complete.

DS40001762A-page 14

 2014 Microchip Technology Inc.

MCS3122

6.1

Decoder Operation

6.0

INTEGRATING MCS3122 INTO

A SYSTEM

The decoder waits until a transmission is received. The

received serial number is compared to the EEPROM

table of learned transmitters to first determine if this

transmitter’s use is allowed in the system. If from a

paired transmitter, the transmission is decrypted using

the stored crypt key and authenticated via the

Discrimination bits for appropriate crypt key usage. If

the decryption is valid, the synchronization value is

evaluated (see Figure 6-1).

FIGURE 6-1:

TYPICAL DECODER

OPERATION

Rev. 20-000013A

1/29/2014

Start

6.2

Synchronization with a Decoder

No

Transmission

Received?

Note:

The synchronization method described in

this section is an exemplar method. It may

be altered to fit the needs and capabilities

of a particular system.

Yes

The KEELOQ technology includes a sophisticated

synchronization technique that does not require the

calculation and storage of future codes. The technique

securely blocks invalid transmission while providing

Does

Serial

Number

Match?

transparent

resynchronization

to

transmitters

inadvertently activated away from the receiver.

Yes

Figure 6-2 shows three-partition,

a

rotating

Decrypt Transmission

Synchronization window. The size of each window is

optional but the technique is fundamental. Each time a

transmission is authenticated, the intended function is

executed and the transmission’s synchronization

counter value is stored in EEPROM. From the currently

stored counter value there is an initial Single Operation

Forward window of 16 codes. If the difference between

a received synchronization counter and the last stored

counter is within 16, the intended function will be

executed on a single button press and the new

synchronization counter will be stored. Storing the new

synchronization counter value effectively rotates the

entire Synchronization window.

Is

No

Decryption

Valid?

Yes

Execute

Command and

Update Counter

Yes

Is Counter

Within 16?

A

Double Operation (Resynchronization) window

further exists from the Single Operation window up to

8M code forward of the currently stored counter value.

It is referred to as Double Operation because a

transmission with a synchronization counter in this

window will require an additional, sequential counter

transmission prior to executing the intended function.

Upon receiving the sequential transmission the

decoder executes the intended function and stores the

synchronization counter value. This resynchronization

occurs transparently to the user, as it is human nature

to press the button a second time if the first was

unsuccessful.

No

Is Counter

Within 32K?

Yes

Save Counter in

Temporary Location

The third window is a Blocked window ranging from the

Double Operation window to the currently stored

synchronization counter value. Any transmission with

synchronization counter value within this window will

be ignored. This window excludes previously used

code-grabbed transmissions from accessing the

system.

 2014 Microchip Technology Inc.

DS40001762A-page 15

MCS3122

FIGURE 6-2:

SYNCHRONIZATION WINDOW

Entire window rotates

to eliminate use of

previously used codes

Blocked

Window

(8M Codes)

Stored

Synchronization

Counter Value

Double Operation

(Resynchronization

Window)

Single Operation

Window

(8M Codes)

(16 Codes)

The main benefit of hopping codes is to prevent the

retransmission of captured code words. This works

very well for code words which the receiver decodes.

Its weakness is that, if a code is captured when the

receiver misses it, the code may trick the receiver once

if it is used before the next valid transmission. The

receiver should increment the counter on questionable

code word receptions. The transmitter should use

separate buttons for lock and unlock functions. A

different method would be to require two different

buttons in sequence to gain access.

6.3

Security Considerations

The strength of this security is based on keeping a

secret inside the transmitter that can be verified by

encrypted transmissions to a trained receiver. The

transmitter’s secret is the manufacturer’s key, not the

encryption algorithm. If that key is compromised, then

a smart transceiver can capture any serial number,

create a valid code word and trick all receivers trained

with that serial number. The key cannot be read from

the EEPROM without costly die probing, but it can be

calculated by brute force decryption attacks on

transmitted code words. The cost for these attacks

should exceed what the manufacturer would want to

protect.

There are more ways to make KEELOQ systems more

secure, but they all have trade-offs. The user should

find a balance between security, design effort and

usability, particularly in failure modes. For example, if a

button sticks or kids play with it, the counter should not

advance into the Blocked Code window, rendering the

transmitter useless or requiring retraining.

To protect the security of other receivers with the same

manufacturer’s code, the manufacturer should use the

random seed for secure learn. It is a second secret that

is unique for each transmitter. If a manufacturer’s key is

compromised, clone transmitters can be created, but

without the unique seed, they have to be relearned by

the receiver. In the same way, if the transmissions are

decrypted by brute force on a computer, the random

seed hides the manufacturer’s key and prevents more

than one transmitter from being compromised.

The length of the code word at these baud rates make

brute force attacks that guess the hopping code take

years. To make the receiver less susceptible to this

attack, it should test all bits in the decrypted code for

the correct value, not just the low counter bits and

function code.

DS40001762A-page 16

 2014 Microchip Technology Inc.

MCS3122

7.0

7.1

ELECTRICAL SPECIFICATIONS

(†)

Absolute Maximum Ratings

Ambient temperature under bias........................................................................................................ -40°C to +85°C

Storage temperature ........................................................................................................................ -55°C to +150°C

Voltage on pins with respect to VSS

on VDD pin ............................................................................................................................................. 0-3.9V

on all other pins ............................................................................................................ -0.3V to (VDD + 0.3V)

Maximum current

on any output pin ................................................................................................................................ 25 mA

† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the

device. This is a stress rating only and functional operation of the device at those or any other conditions above those

indicated in the operation listings of this specification is not implied. Exposure above maximum rating conditions for

extended periods may affect device reliability.

7.2

Standard Operating Conditions

The standard operating conditions for any device are defined as:

Operating Voltage:

Operating Temperature:

VDDMIN VDD VDDMAX

TA_MIN TA TA_MAX

VDD — Operating Supply Voltage

VDDMIN ................................................................................................................................................... +2.0V

VDDMAX .................................................................................................................................................. +3.7V

TA — Operating Ambient Temperature Range

TA_MIN .................................................................................................................................................... -40°C

TA_MAX................................................................................................................................................... +85°C

IDD — Supply Current

At 315 MHz, +10 dBm, FSK, typical⁽¹⁾................................................................................................ +15 mA

At 315 MHz, +10 dBm, OOK, typical⁽¹⁾............................................................................................... +11 mA

At 315 MHz, +0 dBm, FSK, typical⁽¹⁾.................................................................................................... +9 mA

At 915 MHz, +10 dBm, FSK, typical⁽¹⁾............................................................................................. +17.5 mA

At 915 MHz, +0 dBm, FSK, typical⁽¹⁾............................................................................................... +10.5 mA

IPD — Standby Current

VDD = 3V, typical⁽¹⁾............................................................................................................................ +0.23 µA

VIH — Input High Voltage, minimum.............................................................................................. 0.25 VDD + 0.8V

VIL — Input Low Voltage, maximum ..........................................................................................................0.15 VDD

VOH — Output High Voltage

IOH = 3 mA, VDD = 3.3V, minimum..................................................................................................VDD – 0.7V

VOL — Output Low Voltage

IOL = 6 mA, VDD = 3.3V, maximum .........................................................................................................+0.6V

ILED — LED Sink Current, maximum .......................................................................................................... +25 mA

Note 1: Typical values are at 25°C.

 2014 Microchip Technology Inc.

DS40001762A-page 17

MCS3122

8.0

8.1

PACKAGING INFORMATION

Package Marking Information

14-Lead TSSOP (4.4 mm)

Example

XXXXXXXX

YYWW

MCS3122

1409

017

NNN

Legend: XX...X Customer-specific information

Y

YY

WW

NNN

Year code (last digit of calendar year)

Year code (last 2 digits of calendar year)

Week code (week of January 1 is week ‘01’)

Alphanumeric traceability code

Pb-free JEDEC^®designator for Matte Tin (Sn)

e

3

*

This package is Pb-free. The Pb-free JEDEC designator (

can be found on the outer packaging for this package.

)

e3

Note: In the event the full Microchip part number cannot be marked on one line, it will

be carried over to the next line, thus limiting the number of available

characters for customer-specific information.

*

Standard PIC^®device marking consists of Microchip part number, year code, week code, and traceability

code. For PIC device marking beyond this, certain price adders apply. Please check with your Microchip

Sales Office. For QTP devices, any special marking adders are included in QTP price.

DS40001762A-page 18

 2014 Microchip Technology Inc.

MCS3122

8.2

Package Details

The following sections give the technical details of the packages.

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

 2014 Microchip Technology Inc.

DS40001762A-page 19

MCS3122

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

DS40001762A-page 20

 2014 Microchip Technology Inc.

MCS3122

Note: For the most current package drawings, please see the Microchip Packaging Specification located at

http://www.microchip.com/packaging

 2014 Microchip Technology Inc.

DS40001762A-page 21

MCS3122

APPENDIX A: REVISION HISTORY

Revision A (October 2014)

Initial release of this document.

DS40001762A-page 22

 2014 Microchip Technology Inc.

MCS3122

THE MICROCHIP WEB SITE

CUSTOMER SUPPORT

Microchip provides online support via our WWW site at

www.microchip.com. This web site is used as a means

to make files and information easily available to

customers. Accessible by using your favorite Internet

browser, the web site contains the following

information:

Users of Microchip products can receive assistance

through several channels:

• Distributor or Representative

• Local Sales Office

• Field Application Engineer (FAE)

• Technical Support

• Product Support – Data sheets and errata,

application notes and sample programs, design

resources, user’s guides and hardware support

documents, latest software releases and archived

software

Customers

should

contact

their

distributor,

representative or Field Application Engineer (FAE) for

support. Local sales offices are also available to help

customers. A listing of sales offices and locations is

included in the back of this document.

• General Technical Support – Frequently Asked

Questions (FAQ), technical support requests,

online discussion groups, Microchip consultant

program member listing

Technical support is available through the web site

at: http://microchip.com/support.

• Business of Microchip – Product selector and

ordering guides, latest Microchip press releases,

listing of seminars and events, listings of

Microchip sales offices, distributors and factory

representatives

CUSTOMER CHANGE NOTIFICATION

SERVICE

Microchip’s customer notification service helps keep

customers current on Microchip products. Subscribers

will receive e-mail notification whenever there are

changes, updates, revisions or errata related to a

specified product family or development tool of interest.

To register, access the Microchip web site at

www.microchip.com. Under “Support”, click on

“Customer Change Notification” and follow the

registration instructions.

 2014 Microchip Technology Inc.

DS40001762A-page 23

MCS3122

PRODUCT IDENTIFICATION SYSTEM

To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.

(1)

[X]

PART NO.

X

/XX

XXX

-

Examples:

a) MCS3122 - I/ST

Device Tape and Reel

Option

Temperature

Range

Package

Pattern

Industrial temperature,

TSSOP package

Device:

MCS3122

Tape and Reel

Option:

Blank = Standard packaging (tube or tray)

T

= Tape and Reel⁽¹⁾

Temperature

Range:

I

=

-40C to +85C (Industrial)

Package:⁽²⁾

Pattern:

ST

=

TSSOP

Note 1:

Tape and Reel identifier only appears in the

catalog part number description. This

identifier is used for ordering purposes and is

not printed on the device package. Check

with your Microchip Sales Office for package

availability with the Tape and Reel option.

QTP, SQTP, Code or Special Requirements

(blank otherwise)

2:

For other small form-factor package

availability and marking information, please

visit www.microchip.com/packaging or

contact your local sales office.

DS40001762A-page 24

 2014 Microchip Technology Inc.

Note the following details of the code protection feature on Microchip devices:

•

Microchip products meet the specification contained in their particular Microchip Data Sheet.

•

Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the

intended manner and under normal conditions.

•

There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our

knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data

Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

•

Microchip is willing to work with the customer who is concerned about the integrity of their code.

Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not

mean that we are guaranteeing the product as “unbreakable.”

Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our

products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts

allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Information contained in this publication regarding device

applications and the like is provided only for your convenience

and may be superseded by updates. It is your responsibility to

ensure that your application meets with your specifications.

MICROCHIP MAKES NO REPRESENTATIONS OR

WARRANTIES OF ANY KIND WHETHER EXPRESS OR

IMPLIED, WRITTEN OR ORAL, STATUTORY OR

OTHERWISE, RELATED TO THE INFORMATION,

INCLUDING BUT NOT LIMITED TO ITS CONDITION,

QUALITY, PERFORMANCE, MERCHANTABILITY OR

FITNESS FOR PURPOSE. Microchip disclaims all liability

arising from this information and its use. Use of Microchip

devices in life support and/or safety applications is entirely at

the buyer’s risk, and the buyer agrees to defend, indemnify and

hold harmless Microchip from any and all damages, claims,

suits, or expenses resulting from such use. No licenses are

conveyed, implicitly or otherwise, under any Microchip

intellectual property rights.

Trademarks

The Microchip name and logo, the Microchip logo, dsPIC,

FlashFlex, flexPWR, JukeBlox, KEELOQ, KEELOQ logo, Kleer,

LANCheck, MediaLB, MOST, MOST logo, MPLAB,

32

OptoLyzer, PIC, PICSTART, PIC logo, RightTouch, SpyNIC,

SST, SST Logo, SuperFlash and UNI/O are registered

trademarks of Microchip Technology Incorporated in the

U.S.A. and other countries.

The Embedded Control Solutions Company and mTouch are

registered trademarks of Microchip Technology Incorporated

in the U.S.A.

Analog-for-the-Digital Age, BodyCom, chipKIT, chipKIT logo,

CodeGuard, dsPICDEM, dsPICDEM.net, ECAN, In-Circuit

Serial Programming, ICSP, Inter-Chip Connectivity, KleerNet,

KleerNet logo, MiWi, MPASM, MPF, MPLAB Certified logo,

MPLIB, MPLINK, MultiTRAK, NetDetach, Omniscient Code

Generation, PICDEM, PICDEM.net, PICkit, PICtail,

RightTouch logo, REAL ICE, SQI, Serial Quad I/O, Total

Endurance, TSHARC, USBCheck, VariSense, ViewSpan,

WiperLock, Wireless DNA, and ZENA are trademarks of

Microchip Technology Incorporated in the U.S.A. and other

countries.

SQTP is a service mark of Microchip Technology Incorporated

in the U.S.A.

Silicon Storage Technology is a registered trademark of

Microchip Technology Inc. in other countries.

GestIC is a registered trademarks of Microchip Technology

Germany II GmbH & Co. KG, a subsidiary of Microchip

Technology Inc., in other countries.

All other trademarks mentioned herein are property of their

respective companies.

ISBN: 978-1-63276-724-0

QUALITY MANAGEMENT SYSTEM

CERTIFIED BY DNV

Microchip received ISO/TS-16949:2009 certification for its worldwide

headquarters, design and wafer fabrication facilities in Chandler and

Tempe, Arizona; Gresham, Oregon and design centers in California

and India. The Company’s quality system processes and procedures

are for its PIC^®MCUs and dsPIC^®DSCs, KEELOQ^®code hopping

devices, Serial EEPROMs, microperipherals, nonvolatile memory and

analog products. In addition, Microchip’s quality system for the design

and manufacture of development systems is ISO 9001:2000 certified.

== ISO/TS 16949 ==

 2014 Microchip Technology Inc.

DS40001762A-page 25

Worldwide Sales and Service

AMERICAS

ASIA/PACIFIC

EUROPE

Corporate Office

2355 West Chandler Blvd.

Chandler, AZ 85224-6199

Tel: 480-792-7200

Fax: 480-792-7277

Technical Support:

http://www.microchip.com/

support

Asia Pacific Office

Suites 3707-14, 37th Floor

Tower 6, The Gateway

Harbour City, Kowloon

Hong Kong

Tel: 852-2943-5100

Fax: 852-2401-3431

India - Bangalore

Tel: 91-80-3090-4444

Fax: 91-80-3090-4123

Austria - Wels

Tel: 43-7242-2244-39

Fax: 43-7242-2244-393

Denmark - Copenhagen

Tel: 45-4450-2828

Fax: 45-4485-2829

India - New Delhi

Tel: 91-11-4160-8631

Fax: 91-11-4160-8632

France - Paris

Tel: 33-1-69-53-63-20

Fax: 33-1-69-30-90-79

India - Pune

Tel: 91-20-3019-1500

Australia - Sydney

Tel: 61-2-9868-6733

Fax: 61-2-9868-6755

Web Address:

www.microchip.com

Japan - Osaka

Tel: 81-6-6152-7160

Fax: 81-6-6152-9310

Germany - Dusseldorf

Tel: 49-2129-3766400

Atlanta

Duluth, GA

Tel: 678-957-9614

Fax: 678-957-1455

China - Beijing

Tel: 86-10-8569-7000

Fax: 86-10-8528-2104

Germany - Munich

Tel: 49-89-627-144-0

Fax: 49-89-627-144-44

Japan - Tokyo

Tel: 81-3-6880- 3770

Fax: 81-3-6880-3771

China - Chengdu

Tel: 86-28-8665-5511

Fax: 86-28-8665-7889

Austin, TX

Tel: 512-257-3370

Germany - Pforzheim

Tel: 49-7231-424750

Korea - Daegu

Tel: 82-53-744-4301

Fax: 82-53-744-4302

Boston

China - Chongqing

Tel: 86-23-8980-9588

Fax: 86-23-8980-9500

Italy - Milan

Tel: 39-0331-742611

Fax: 39-0331-466781

Westborough, MA

Tel: 774-760-0087

Fax: 774-760-0088

Korea - Seoul

Tel: 82-2-554-7200

Fax: 82-2-558-5932 or

82-2-558-5934

China - Hangzhou

Tel: 86-571-8792-8115

Fax: 86-571-8792-8116

Italy - Venice

Tel: 39-049-7625286

Chicago

Itasca, IL

Tel: 630-285-0071

Fax: 630-285-0075

Netherlands - Drunen

Tel: 31-416-690399

Fax: 31-416-690340

Malaysia - Kuala Lumpur

Tel: 60-3-6201-9857

Fax: 60-3-6201-9859

China - Hong Kong SAR

Tel: 852-2943-5100

Fax: 852-2401-3431

Cleveland

Independence, OH

Tel: 216-447-0464

Fax: 216-447-0643

Poland - Warsaw

Tel: 48-22-3325737

Malaysia - Penang

Tel: 60-4-227-8870

Fax: 60-4-227-4068

China - Nanjing

Tel: 86-25-8473-2460

Fax: 86-25-8473-2470

Spain - Madrid

Tel: 34-91-708-08-90

Fax: 34-91-708-08-91

Dallas

Addison, TX

Tel: 972-818-7423

Fax: 972-818-2924

Philippines - Manila

Tel: 63-2-634-9065

Fax: 63-2-634-9069

China - Qingdao

Tel: 86-532-8502-7355

Fax: 86-532-8502-7205

Sweden - Stockholm

Tel: 46-8-5090-4654

Singapore

Tel: 65-6334-8870

Fax: 65-6334-8850

Detroit

Novi, MI

Tel: 248-848-4000

China - Shanghai

Tel: 86-21-5407-5533

Fax: 86-21-5407-5066

UK - Wokingham

Tel: 44-118-921-5800

Fax: 44-118-921-5820

Taiwan - Hsin Chu

Tel: 886-3-5778-366

Fax: 886-3-5770-955

Houston, TX

Tel: 281-894-5983

China - Shenyang

Tel: 86-24-2334-2829

Fax: 86-24-2334-2393

Indianapolis

Noblesville, IN

Tel: 317-773-8323

Fax: 317-773-5453

Taiwan - Kaohsiung

Tel: 886-7-213-7830

China - Shenzhen

Tel: 86-755-8864-2200

Fax: 86-755-8203-1760

Taiwan - Taipei

Tel: 886-2-2508-8600

Fax: 886-2-2508-0102

Los Angeles

China - Wuhan

Tel: 86-27-5980-5300

Fax: 86-27-5980-5118

Mission Viejo, CA

Tel: 949-462-9523

Fax: 949-462-9608

Thailand - Bangkok

Tel: 66-2-694-1351

Fax: 66-2-694-1350

China - Xian

Tel: 86-29-8833-7252

Fax: 86-29-8833-7256

New York, NY

Tel: 631-435-6000

San Jose, CA

Tel: 408-735-9110

China - Xiamen

Tel: 86-592-2388138

Fax: 86-592-2388130

Canada - Toronto

Tel: 905-673-0699

Fax: 905-673-6509

China - Zhuhai

Tel: 86-756-3210040

Fax: 86-756-3210049

03/25/14

DS40001762A-page 26

 2014 Microchip Technology Inc.


型号：	MCS3122
厂家：	MICROCHIP
描述：	MCS3122 Advanced KEELOQÂ® Technology Encoder Data Sheet
文件：	总26页 (文件大小：416K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

MCS3122 [MICROCHIP]

相关型号：

SI9130DB

SI9135LG-T1

SI9135LG-T1-E3

SI9135_11

SI9136_11

SI9130CG-T1-E3

SI9130LG-T1-E3

SI9130_11

SI9137

SI9137DB

SI9137LG

SI9122E