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# memory.h File Reference

## Detailed Description

Header file for EEPROM and SRAM variables and support functions.

This file contains variable declarations and function prototypes for common data in EEPROM and SRAM. The implementation is found in the memory.c file. Note that the cryptographic key management PC tools relies upon the specific placement in EEPROM of the serialNo, nextCounterValue, secretKey and sharedKey variables.

- File: memory.h
- Compiler: IAR EWAVR 4.11B
- Supported devices: ATtiny45/85
- AppNote: AVR411 - Secure Rolling Code Algorithm for Wireless Link

Author:
  Atmel Corporation: http://www.atmel.com
  Support email: avr@atmel.com

Name

Revision
  1193

Date
  2006-10-31 14:21:08 +0100 (ti, 31 okt 2006)

Copyright (c) 2006, Atmel Corporation All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. The name of ATMEL may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ATMEL ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Definition in file memory.h.

`#include "common.h"`
`#include "config.h"`

Include dependency graph for memory.h:

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## Data Structures
struct | MessagePayload
| Structure containing message payload without MAC. More...
union | SharedBlock
## Functions
void | createMessage (COMMAND_CODE_TYPE commandCode)
void | initializeMessage (void)
void | startCounterUpdate ()
void | waitForCounterUpdate ()
## Variables
byte | cryptoBlock [BLOCK_SIZE+1]
__no_init byte __eeprom secretKey[KEY_SIZE] | SECRET_KEY_ADDRESS
__no_init SEQ_COUNTER_TYPE __eeprom nextCounterValue | SEQ_COUNTER_ADDRESS
__no_init SERIAL_NO_TYPE __eeprom serialNo | SERIAL_NO_ADDRESS
__no_init byte __eeprom sharedKey[KEY_SIZE] | SHARED_KEY_ADDRESS
SharedBlock | sharedBlock

## Function Documentation

void createMessage | ( | COMMAND_CODE_TYPE | commandCode | ) |

Prepare non-constant fields for message payload in 'sharedBlock'.

Definition at line 79 of file memory.c.

References MessagePayload::commandCode, MessagePayload::counterValue, SharedBlock::messagePayload, and sharedBlock.

Referenced by transmitCommandMessage().

    00080 {
    00081         sharedBlock.messagePayload.commandCode = commandCode;
    00082         sharedBlock.messagePayload.counterValue = nextCounterValue;
    00083 }

void initializeMessage | ( | void |  | ) |

Prepare constant fields for message payload in 'sharedBlock'.

Definition at line 69 of file memory.c.

References SharedBlock::messagePayload, MessagePayload::preamble, MessagePayload::serialNo, and sharedBlock.

Referenced by main(), and transmitTeachMessage().

    00070 {
    00071         // The preamble is used as a synch-and-start indicator for
    00072         // the RF receiver.
    00073         sharedBlock.messagePayload.preamble = 0xfe; // 11111110
    00074         sharedBlock.messagePayload.serialNo = serialNo;
    00075 }

void startCounterUpdate | ( |  | ) |

Start interrupt controlled update of 'nextCounterValue' in EEPROM.

Definition at line 92 of file memory.c.

References counterBytesLeft, and SEQ_COUNTER_BYTES.

Referenced by transmitCommandMessage().

    00093 {
    00094         // Make sure EEPROM is ready.
    00095         do {} while( EECR & (1<<EEWE) );
    00096         // Prepare control variables.
    00097         EEDR = 0xff; // 0xff indicates that we just started.
    00098         EEAR = (uint16_t) &nextCounterValue;
    00099         counterBytesLeft = SEQ_COUNTER_BYTES;
    00100         // Enable EEPROM Ready Interrupt.
    00101         EECR |= (1<<EERIE);
    00102 }

void waitForCounterUpdate | ( |  | ) |

Wait for counter value update to finish.

Definition at line 106 of file memory.c.

References counterBytesLeft.

Referenced by transmitCommandMessage().

    00107 {
    00108         while( counterBytesLeft ) { __sleep(); }
    00109 }

## Variable Documentation

byte cryptoBlock[BLOCK_SIZE+1]

Common workspace for encrypting and decrypting.

Definition at line 62 of file memory.c.

Referenced by main(), transmitCommandMessage(), and transmitTeachMessage().

__no_init byte __eeprom secretKey [ KEY_SIZE ] SECRET_KEY_ADDRESS

Secret key storage in EEPROM.

Definition at line 73 of file memory.h.

__no_init SEQ_COUNTER_TYPE __eeprom nextCounterValue SEQ_COUNTER_ADDRESS

Counter value storage in EEPROM.

Definition at line 70 of file memory.h.

__no_init SERIAL_NO_TYPE __eeprom serialNo SERIAL_NO_ADDRESS

Serial number storage in EEPROM.

Definition at line 68 of file memory.h.

__no_init byte __eeprom sharedKey [ KEY_SIZE ] SHARED_KEY_ADDRESS

Shared key storage in EEPROM.

Definition at line 75 of file memory.h.

union SharedBlock sharedBlock

Common workspace for message payloads and a second crypto block.

Definition at line 63 of file memory.c.

Referenced by createMessage(), initializeMessage(), transmitCommandMessage(), and transmitTeachMessage().

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