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SPI EEPROM with a Explorer 16 Board

 
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pebbert9



Joined: 31 Dec 2010
Posts: 39

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SPI EEPROM with a Explorer 16 Board
PostPosted: Fri Dec 31, 2010 12:45 am     Reply with quote
Hello,

I am trying to get the 25LC256 EEPROM on an Explorer 16 board to work.

I found this http://www.ccsinfo.com/forum/viewtopic.php?t=28199&start=1 which seems to explain everything clearly.

I've edited the SELECT, CLK, DI, and DO pins to conform to the Explorer 16 board, but when I look at the pins on a scope I'm not getting any signals to them.

I am using PCWHD v4.116

I then found this driver which doesn't use the built-in SPI functions http://www.ccsinfo.com/forum/viewtopic.php?t=38064 . This driver does drive signals to the pins.

The SPI port doesn't seem to be setting up correctly. Any ideas why I am not getting any signals to the CLK, DI, and DO pins?

Here is the test code:
Code:
#include <24FJ128GA010.h>
#device ICD=TRUE

#fuses NOIESO        // No 2-speed Start Up
#fuses NOJTAG        // No JTAG
#fuses NOPROTECT     // No Memory Protection
#fuses NOWDT         // No WatchDog Timer
#fuses NODEBUG       // Debug Mode.
#FUSES CKSFSM        // Clock Switching is enabled, fail Safe clock monitor is enabled

#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_F4, rcv=PIN_F5, ERRORS)

#define SPI_MODE_0_0 0x4000
#define SPI_MODE_0_1 0x0000
#define SPI_MODE_1_0 0x0010
#define SPI_MODE_1_1 0x4010

// If your hardware SPI pins are different than the
// ones used on the 16F877, then define them here
// and un-comment this section.
#define EEPROM_SELECT PIN_D12
#define EEPROM_CLK    PIN_G6
#define EEPROM_DI     PIN_G8
#define EEPROM_DO     PIN_G7

#include <25LC640_Hardware_SPI.c>
   
#include <STDLIB.H>
//========================
void main()
{
int8 data;
int8 wrote;
int16 addr;
int16 errors = 0;
     
init_ext_eeprom();
     
// Fill eeprom with random data.
printf("\n\r");
printf("writing");

srand(0x55);

for(addr = 0; addr < EEPROM_SIZE; addr++)
   {
    write_ext_eeprom(addr, (int8)rand());
    if((int8)addr == 0)
       putc('.');
   }

// Read the eeprom and check for errors.
printf("\n\r");
printf("reading");

srand(0x55);

for(addr = 0; addr < EEPROM_SIZE; addr++)
   {
    data = read_ext_eeprom(addr);
    wrote = (int8)rand();
    if(data != wrote)
      {
       printf("%lx: read %x, should be %x\n\r", addr, data, wrote);
       errors++;
       if(errors >= 10)
          break;
      }

    if((int8)addr == 0)
       putc('.');
   }

printf("\n\r");
printf("done\n\r");

while(1);
}


The driver is identical to the post.

Code:

#ifndef EEPROM_SELECT
#define EEPROM_SELECT PIN_C2
#define EEPROM_CLK    PIN_C3
#define EEPROM_DI     PIN_C5
#define EEPROM_DO     PIN_C4
#endif

#define EEPROM_ADDRESS long int
#define EEPROM_SIZE    8192

void init_ext_eeprom()
{
output_high(EEPROM_SELECT);   
setup_spi(SPI_MASTER | SPI_MODE_0_0 | SPI_CLK_DIV_16 );
}

//--------------------------------
int1 ext_eeprom_ready(void)
{
int8 data;

output_low(EEPROM_SELECT);
spi_write(0x05);
data = spi_read(0);
output_high(EEPROM_SELECT);
return(!bit_test(data, 0));
}

//--------------------------------
void write_ext_eeprom(EEPROM_ADDRESS address, BYTE data)
{
while(!ext_eeprom_ready());

output_low(EEPROM_SELECT);
spi_write(0x06);
output_high(EEPROM_SELECT);

output_low(EEPROM_SELECT);
spi_write(0x02);
spi_write(address >> 8);
spi_write(address);
spi_write(data);
output_high(EEPROM_SELECT);
}
//--------------------------------

BYTE read_ext_eeprom(EEPROM_ADDRESS address)
{
int8 data;

while(!ext_eeprom_ready());

output_low(EEPROM_SELECT);
spi_write(0x03);
spi_write(address >> 8);
spi_write(address);

data = spi_read(0);
output_high(EEPROM_SELECT);

return(data);
}
FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

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PostPosted: Fri Dec 31, 2010 2:03 am     Reply with quote
The SPI mode coding in your post is completely invalid for PIC24, they are for PIC16. Because CCS has recently fixed a bug in PIC24 mode coding, it's a bit complicated. See:
http://www.ccsinfo.com/forum/viewtopic.php?t=41421
pebbert9



Joined: 31 Dec 2010
Posts: 39

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PostPosted: Sat Jan 01, 2011 12:06 am     Reply with quote
It turns out my issue was that the EEPROM is connected to SPI2 and I was trying to initialize SPI1 with SPI2's pins.

I have the EEPROM on the Explorer 16 board working with the following code.

Test Code:
Code:
#include <24FJ128GA010.h>
#device ICD=TRUE

#fuses NOWDT         // No WatchDog Timer
#FUSES CKSFSM        // Clock Switching is enabled, fail Safe clock monitor is enabled

#use delay(clock=8000000)
#use rs232(baud=9600, xmit=PIN_F4, rcv=PIN_F5, ERRORS)

#include <25LC256_SPI.c>
   
#include <STDLIB.H>
//========================
void main()
{
int8 data;
int8 wrote;
int16 addr;
int16 errors = 0;
     
init_ext_eeprom();
     
// Fill eeprom with random data.
printf("\n\r");
printf("writing");

srand(0x54);

for(addr = 0; addr < 16; addr++)    // Change addr < 16 to addr < EEPROM_SIZE to write to all memory locations
   {
    write_ext_eeprom(addr, (int8)rand());
    if((int8)addr == 0)
       putc('.');
   }

// Read the eeprom and check for errors.
printf("\n\r");
printf("reading");

srand(0x54);

for(addr = 0; addr < 16; addr++)    // Change addr < 16 to addr < EEPROM_SIZE to read from all memory locations
   {
    data = read_ext_eeprom(addr);
    wrote = (int8)rand();
    if(data != wrote)
      {
       printf("%lx: read %x, should be %x\n\r", addr, data, wrote);
       errors++;
       if(errors >= 10)
          break;
      }

    if((int8)addr == 0)
       putc('.');
   }

printf("\n\r");
printf("done\n\r");

while(1);
}


Place the following driver into 25LC256_SPI.c

Code:

#define EEPROM_SELECT PIN_D12

#define EEPROM_ADDRESS long int
#define EEPROM_SIZE    32678

void init_ext_eeprom()
{
output_high(EEPROM_SELECT);   
setup_spi2(SPI_MASTER | SPI_XMIT_L_TO_H | SPI_CLK_DIV_4 );
}

//--------------------------------
int1 ext_eeprom_ready(void)
{
int8 data;

output_low(EEPROM_SELECT);
spi_write2(0x05);
data = spi_read2(0);
output_high(EEPROM_SELECT);
return(!bit_test(data, 0));
}

//--------------------------------
void write_ext_eeprom(EEPROM_ADDRESS address, BYTE data)
{
while(!ext_eeprom_ready());

output_low(EEPROM_SELECT);
spi_write2(0x06);
output_high(EEPROM_SELECT);

output_low(EEPROM_SELECT);
spi_write2(0x02);
spi_write2(address >> 8);
spi_write2(address);
spi_write2(data);
output_high(EEPROM_SELECT);
}
//--------------------------------

BYTE read_ext_eeprom(EEPROM_ADDRESS address)
{
int8 data;

while(!ext_eeprom_ready());

output_low(EEPROM_SELECT);
spi_write2(0x03);
spi_write2(address >> 8);
spi_write2(address);

data = spi_read2(0);
output_high(EEPROM_SELECT);

return(data);
}
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