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Problem 24FJ256GB110 and 25LC256

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microlo75

Joined: 13 Apr 2010
Posts: 23

Problem 24FJ256GB110 and 25LC256

Posted: Wed Oct 06, 2010 10:34 am

Reply with quote

Hello,
I have this problem using a 24FJ256GB110 and 25LC256

Code:

#ifndef EEPROM_SELECT

#define EEPROM_SELECT PIN_D12
#define EEPROM_CLK PIN_G6
#define EEPROM_DI PIN_G8
#define EEPROM_DO PIN_G7

#endif

#define EEPROM_ADDRESS long int
#define EEPROM_SIZE 262144

void init_ext_eeprom() {
output_high(EEPROM_SELECT);
output_low(EEPROM_DI);
output_low(EEPROM_CLK);
}

BOOLEAN ext_eeprom_ready() {
BYTE cmd[1], i, data;

cmd[0] = 0x05; //rdsr opcode

output_low(EEPROM_SELECT);

for(i=1; i<=8; ++i) {
output_bit(EEPROM_DI, shift_left(cmd,1,0));
output_high(EEPROM_CLK); //data latches
output_low(EEPROM_CLK); //back to idle
}

for(i=1; i<=8; ++i) {
output_high(EEPROM_CLK); //data latches
shift_left(&data,1,input(EEPROM_DO));
output_low(EEPROM_CLK); //back to idle
}
output_high(EEPROM_SELECT);
return !bit_test(data, 0);
}

void write_ext_eeprom(EEPROM_ADDRESS address, BYTE data) {
BYTE cmd[4];
BYTE i;
BYTE wren;
wren=0x06;
cmd[0]=data;
cmd[1]=address;
cmd[2]=(address>>8);
cmd[3]=0x02;

// Wait until the eeprom is done with a previous write
while(!ext_eeprom_ready());

output_low(EEPROM_SELECT);
for(i=0; i<8; ++i)
{
output_bit(EEPROM_DI, shift_left(&wren,1,0));
output_high(EEPROM_CLK);
output_low(EEPROM_CLK);
}
output_high(EEPROM_SELECT);
output_low(EEPROM_SELECT);
for(i=0; i<32; ++i)
{
output_bit(EEPROM_DI, shift_left(cmd,4,0));
output_high(EEPROM_CLK);
output_low(EEPROM_CLK);
}
output_high(EEPROM_SELECT);
}

BYTE read_ext_eeprom(EEPROM_ADDRESS address) {
BYTE cmd[3];
BYTE i,data;
cmd[0]=address;
cmd[1]=(address>>8);
cmd[2]=0x03;

// Wait until the eeprom is done with a previous write
while(!ext_eeprom_ready());

output_low(EEPROM_SELECT);
for(i=0; i<24; ++i)
{
output_bit(EEPROM_DI, shift_left(cmd,3,0));
output_high(EEPROM_CLK);
output_low(EEPROM_CLK);
}
for(i=0; i<8; ++i)
{
shift_left(&data,1,input(EEPROM_DO));
output_high(EEPROM_CLK);
output_low(EEPROM_CLK);
}
output_high(EEPROM_SELECT);
return(data);
}

the program works, but sometimes there is an error in reading the EEPROM
how is it possible?

example:
about 10 times this routine 2-3 times only the right data!!

Code:

for(slot=0;slot<1000;slot++)
{
usb_cdc_putc(read_ext_eeprom(slot));
delay_us(300);
}

a few bytes are wrong!!!

I could not use the SPI ...
Embarassed

Embarassed

Thanks to all

PCM programmer

Joined: 06 Sep 2003
Posts: 21708

Posted: Wed Oct 06, 2010 12:20 pm

Reply with quote

I don't have the PCD compiler, so I can't help very much.
But, my suggestion is to prove that the SPI interface is the problem.
Change your test to the following:

Quote:

for(slot=0;slot<1000;slot++)
{
usb_cdc_putc((int8)slot);
delay_us(300);
}

This should display incrementing numbers from 0 to 255, several times.
If it fails, the problem is the CDC interface. If it works, the problem may
be in the SPI interface.

microlo75

Joined: 13 Apr 2010
Posts: 23

Solved
Posted: Fri Oct 08, 2010 11:25 pm

With SPI work !!!!! Thanks for reply bye

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