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PsiSwarm/eprom.cpp@0:8a5497a2e366, 2015-10-03 (annotated)

Committer:
jah128
Date:
Sat Oct 03 22:48:50 2015 +0000
Revision:
0:8a5497a2e366
Child:
1:f6356cf1cefc
Initial commit of PsiSwarm API and example code

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jah128 0:8a5497a2e366 1 /** University of York Robotics Laboratory PsiSwarm Library: Eprom Functions Source File
jah128 0:8a5497a2e366 2 *
jah128 0:8a5497a2e366 3 * File: eprom.cpp
jah128 0:8a5497a2e366 4 *
jah128 0:8a5497a2e366 5 * (C) Dr James Hilder, Dept. Electronics & Computer Science, University of York
jah128 0:8a5497a2e366 6 *
jah128 0:8a5497a2e366 7 * PsiSwarm Library Version: 0.2, October 2015
jah128 0:8a5497a2e366 8 *
jah128 0:8a5497a2e366 9 * Functions for accessing the 64Kb EPROM chip and reading the reserved firmware block
jah128 0:8a5497a2e366 10 *
jah128 0:8a5497a2e366 11 * Example:
jah128 0:8a5497a2e366 12 * @code
jah128 0:8a5497a2e366 13 * #include "psiswarm.h"
jah128 0:8a5497a2e366 14 *
jah128 0:8a5497a2e366 15 * int main() {
jah128 0:8a5497a2e366 16 * init();
jah128 0:8a5497a2e366 17 * write_eeprom_byte(0,0xDD); //Writes byte 0xDD in EPROM address 0
jah128 0:8a5497a2e366 18 * char c = read_eeprom_byte(0); //c will hold 0xDD
jah128 0:8a5497a2e366 19 * //Valid address range is from 0 to 65279
jah128 0:8a5497a2e366 20 * }
jah128 0:8a5497a2e366 21 * @endcode
jah128 0:8a5497a2e366 22 */
jah128 0:8a5497a2e366 23
jah128 0:8a5497a2e366 24 #include "psiswarm.h"
jah128 0:8a5497a2e366 25
jah128 0:8a5497a2e366 26 /** Write a single byte to the EPROM
jah128 0:8a5497a2e366 27 *
jah128 0:8a5497a2e366 28 * @param address The address to store the data, range 0-65279
jah128 0:8a5497a2e366 29 * @param data The character to store
jah128 0:8a5497a2e366 30 */
jah128 0:8a5497a2e366 31 void write_eeprom_byte ( int address, char data ){
jah128 0:8a5497a2e366 32 char write_array[3];
jah128 0:8a5497a2e366 33 if(address > 65279){
jah128 0:8a5497a2e366 34 debug("WARNING: Attempt to write to invalid EPROM address: %X",address);
jah128 0:8a5497a2e366 35 }else{
jah128 0:8a5497a2e366 36 write_array[0] = address / 256;
jah128 0:8a5497a2e366 37 write_array[1] = address % 256;
jah128 0:8a5497a2e366 38 write_array[2] = data;
jah128 0:8a5497a2e366 39 primary_i2c.write(EEPROM_ADDRESS, write_array, 3, false);
jah128 0:8a5497a2e366 40 //Takes 5ms to write a page: ideally this could be done with a timer or RTOS
jah128 0:8a5497a2e366 41 wait(0.005);
jah128 0:8a5497a2e366 42 }
jah128 0:8a5497a2e366 43 }
jah128 0:8a5497a2e366 44
jah128 0:8a5497a2e366 45 /** Read a single byte from the EPROM
jah128 0:8a5497a2e366 46 *
jah128 0:8a5497a2e366 47 * @param address The address to read from, range 0-65279
jah128 0:8a5497a2e366 48 * @return The character stored at address
jah128 0:8a5497a2e366 49 */
jah128 0:8a5497a2e366 50 char read_eeprom_byte ( int address ){
jah128 0:8a5497a2e366 51 char address_array [2];
jah128 0:8a5497a2e366 52 address_array[0] = address / 256;
jah128 0:8a5497a2e366 53 address_array[1] = address % 256;
jah128 0:8a5497a2e366 54 char data [1];
jah128 0:8a5497a2e366 55 primary_i2c.write(EEPROM_ADDRESS, address_array, 2, false);
jah128 0:8a5497a2e366 56 primary_i2c.read(EEPROM_ADDRESS, data, 1, false);
jah128 0:8a5497a2e366 57 return data [0];
jah128 0:8a5497a2e366 58 }
jah128 0:8a5497a2e366 59
jah128 0:8a5497a2e366 60 /** Read the next byte from the EPROM, to be called after read_eeprom_byte
jah128 0:8a5497a2e366 61 *
jah128 0:8a5497a2e366 62 * @return The character stored at address after the previous one read from
jah128 0:8a5497a2e366 63 */
jah128 0:8a5497a2e366 64 char read_next_eeprom_byte (){
jah128 0:8a5497a2e366 65 char data [1];
jah128 0:8a5497a2e366 66 primary_i2c.read(EEPROM_ADDRESS, data, 1, false);
jah128 0:8a5497a2e366 67 return data [0];
jah128 0:8a5497a2e366 68 }
jah128 0:8a5497a2e366 69
jah128 0:8a5497a2e366 70 /** Read the data stored in the reserved firmware area of the EPROM
jah128 0:8a5497a2e366 71 *
jah128 0:8a5497a2e366 72 * @return 1 if a valid firmware is read, 0 otherwise
jah128 0:8a5497a2e366 73 */
jah128 0:8a5497a2e366 74 char read_firmware (){
jah128 0:8a5497a2e366 75 char address_array [2] = {255,0};
jah128 0:8a5497a2e366 76 primary_i2c.write(EEPROM_ADDRESS, address_array, 2, false);
jah128 0:8a5497a2e366 77 primary_i2c.read(EEPROM_ADDRESS, firmware_bytes, 20, false);
jah128 0:8a5497a2e366 78 if(firmware_bytes[0] == PSI_BYTE) return 1;
jah128 0:8a5497a2e366 79 return 0;
jah128 0:8a5497a2e366 80 }