syndilights/displayclient/ardupixel/serial2eeprom/serial2eeprom.ino

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// WRITES TO SERIAL EEPROM Arduino
//
// Do this only once on an Arduino,
// Write the Serial of the Arduino in the
// First 6 bytes of the EEPROM
// you find the serial by connecting to usb in /dev/serial/by-id
// usb-Arduino__www.arduino.cc__0042_7533030393435171B1A0-if00
// take the last 6 positions 71B1A0
#include <EEPROM.h>
char sID[7]="71B1A0"; // change this to the serial number on the board
#define EEPROM_MIN_ADDR 0
#define EEPROM_MAX_ADDR 511
//
// Returns true if the address is between the
// minimum and maximum allowed values,
// false otherwise.
//
// This function is used by the other, higher-level functions
// to prevent bugs and runtime errors due to invalid addresses.
//
boolean eeprom_is_addr_ok(int addr) {
return ((addr >= EEPROM_MIN_ADDR) && (addr <= EEPROM_MAX_ADDR));
}
boolean eeprom_write_bytes(int startAddr, const byte* array, int numBytes) {
// counter
int i;
// both first byte and last byte addresses must fall within
// the allowed range
if (!eeprom_is_addr_ok(startAddr) || !eeprom_is_addr_ok(startAddr + numBytes)) {
return false;
}
for (i = 0; i < numBytes; i++) {
EEPROM.write(startAddr + i, array[i]);
}
return true;
}
//
// Writes a string starting at the specified address.
// Returns true if the whole string is successfully written.
// Returns false if the address of one or more bytes
// fall outside the allowed range.
// If false is returned, nothing gets written to the eeprom.
//
boolean eeprom_write_string(int addr, const char* string) {
// actual number of bytes to be written
int numBytes;
// we'll need to write the string contents
// plus the string terminator byte (0x00)
numBytes = strlen(string) + 1;
return eeprom_write_bytes(addr, (const byte*)string, numBytes);
}
//
// Reads the specified number of bytes from the specified address into the provided buffer.
// Returns true if all the bytes are successfully read.
// Returns false if the star or end addresses aren't between
// the minimum and maximum allowed values.
// When returning false, the provided array is untouched.
//
// Note: the caller must ensure that array[] has enough space
// to store at most numBytes bytes.
//
boolean eeprom_read_bytes(int startAddr, byte array[], int numBytes) {
int i;
// both first byte and last byte addresses must fall within
// the allowed range
if (!eeprom_is_addr_ok(startAddr) || !eeprom_is_addr_ok(startAddr + numBytes)) {
return false;
}
for (i = 0; i < numBytes; i++) {
array[i] = EEPROM.read(startAddr + i);
}
return true;
}
//
// Reads a string starting from the specified address.
// Returns true if at least one byte (even only the
// string terminator one) is read.
// Returns false if the start address falls outside
// or declare buffer size os zero.
// the allowed range.
// The reading might stop for several reasons:
// - no more space in the provided buffer
// - last eeprom address reached
// - string terminator byte (0x00) encountered.
// The last condition is what should normally occur.
//
boolean eeprom_read_string(int addr, char* buffer, int bufSize) {
// byte read from eeprom
byte ch;
// number of bytes read so far
int bytesRead;
// check start address
if (!eeprom_is_addr_ok(addr)) {
return false;
}
// how can we store bytes in an empty buffer ?
if (bufSize == 0) {
return false;
}
// is there is room for the string terminator only,
// no reason to go further
if (bufSize == 1) {
buffer[0] = 0;
return true;
}
// initialize byte counter
bytesRead = 0;
// read next byte from eeprom
ch = EEPROM.read(addr + bytesRead);
// store it into the user buffer
buffer[bytesRead] = ch;
// increment byte counter
bytesRead++;
// stop conditions:
// - the character just read is the string terminator one (0x00)
// - we have filled the user buffer
// - we have reached the last eeprom address
while ( (ch != 0x00) && (bytesRead < bufSize) && ((addr + bytesRead) <= EEPROM_MAX_ADDR) ) {
// if no stop condition is met, read the next byte from eeprom
ch = EEPROM.read(addr + bytesRead);
// store it into the user buffer
buffer[bytesRead] = ch;
// increment byte counter
bytesRead++;
}
// make sure the user buffer has a string terminator
// (0x00) as its last byte
if ((ch != 0x00) && (bytesRead >= 1)) {
buffer[bytesRead - 1] = 0;
}
return true;
}
char buf[7];
void setup()
{
Serial.begin(9600);
eeprom_read_string(0,buf, 7); // read from addr 0 into buf 7 chars
if(strncmp(buf,sID,6) != 0) { // only write if not yet written
eeprom_write_string(0, sID); // write to adress 0 the ID
}
}
void loop () {
Serial.println("---");
Serial.print("old value: ");
Serial.println(buf);
Serial.print("new value: ");
Serial.println(sID);
if(strncmp(buf,sID,6) != 0) {
Serial.println("different");
} else {
Serial.println("same");
}
}