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TimothyCarter
Joined: 08 Aug 2016
Posts: 22
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| big variables to EEPROM |
 Posted: Thu Mar 31, 2022 9:51 am |
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Should anyone find this useful, here are some helper functions for reading/writing 16 & 32 bit variables to EEPROM.
Note: as stated in the comments, variables should be stored in sequential bytes of EE.
Download link: https://gitlab.com/smilingtexan/ccs-picc-eeprom-large-var.git
| Code: |
/*
* @file: eeprom_large.c
* @author: T. Carter
* @date: March 30, 2022
*
* This code is to provide methods to read and write 16-bit and 32-bit
* variables to the EEPROM of the PIC (it uses the built-in functions
* for read_eeprom and write_eeprom)
*
*/
#ifndef _STDINT
#include <stdint.h> // need this library from the CCS drivers folder
#endif
// The CCS built-in function read_eeprom will read and return one byte
// from the EEPROM memory. The following two functions are added
// to return a 16-bit and 32-bit unsigned int respectively.
// The macro __EEADDRESS__ is defined in the processor header file as
// either an 8-bit or 16-bit variable depending on EEPROM size.
// For the 16-bit and 32-bit methods of read & write; the addr variable
// should be the EEPROM address of the LSB (least-significant byte)
// Thus, the EEPROM addresses for the 16-bit and 32-bit variables
// should be sequential or things can get really confusing
uint16_t read_eeprom16 (__EEADDRESS__ addr)
{
uint8_t low, high;
low = read_eeprom(addr++); // read from eeprom at addr and then increment addr
high = read_eeprom(addr);
return(make16(high, low));
}
uint32_t read_eeprom32 (__EEADDRESS__ addr)
{
uint8_t low, high;
uint16_t wLow, wHigh;
low = read_eeprom(addr++); // read from eeprom at addr and then increment addr
high = read_eeprom(addr++);
wLow = make16(high, low);
low = read_eeprom(addr++);
high = read_eeprom(addr);
wHigh = make16(high, low);
return(make32(wHigh, wLow));
}
// The following eeprom_write function only writes the data to EEPROM if
// it is different from what is at that addr
void eeprom_write (__EEADDRESS__ addr, uint8_t data)
{
uint8_t temp = read_eeprom(addr);
if (data != temp)
{
write_eeprom(addr, data);
}
}
// The following two functions are provided to write 16-bit and 32-bit
// variables to the EEPROM; similar to the read_eeprom functions above
void write_eeprom16 (__EEADDRESS__ addr, uint16_t data)
{
uint8_t smallData = make8(data, 0);
eeprom_write(addr++, smallData);
smallData = make8(data, 1);
eeprom_write(addr, smallData);
}
void write_eeprom32 (__EEADDRESS__ addr, uint32_t data)
{
uint8_t smallData = make8(data, 0);
eeprom_write(addr++, smallData);
smallData = make8(data, 1);
eeprom_write(addr++, smallData);
smallData = make8(data, 2);
eeprom_write(addr++, smallData);
smallData = make8(data, 3);
eeprom_write(addr, smallData);
}
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_________________
“Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.”
- Eric S. Raymond |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19529
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| Posted: Mon Apr 04, 2022 6:30 am |
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Just FYI, the compiler already has code to do this (and for several more
types as well). Look at 'internal_eeprom.c', which has routines to handle
int1, int16, int32, float, and for PCD, float48, float64 etc.. |
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TimothyCarter
Joined: 08 Aug 2016
Posts: 22
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| I figured CCS had something ... |
| Posted: Tue Apr 12, 2022 3:20 pm |
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| Ttelmah wrote: | Just FYI, the compiler already has code to do this (and for several more
types as well). Look at 'internal_eeprom.c', which has routines to handle
int1, int16, int32, float, and for PCD, float48, float64 etc.. |
I figured they must have had something, but could not find it at the time I wrote this. (Originally written a couple of years ago.)
_________________
“Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.”
- Eric S. Raymond |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19529
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| Posted: Mon Apr 25, 2022 1:14 am |
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I think perhaps they need to do something like the 'readme', with a list
of the driver files and what they do.
The file goes back to 2012, so should have been with your compiler
'a couple of years ago'.  |
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