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epideath
Joined: 07 Jun 2006
Posts: 47
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| 25LC256 and PIC4525 |
 Posted: Mon Sep 11, 2006 11:14 am |
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EDIT: Thanks for catching that PCM_Programmer. I wish that was disabled by defalt hehe
This might be a bit off-topic, well unless it really is a programming
error 
I have the following code working with no problems on a 25LC640, 32K serial EEPROM. When I try communicating to a 25LC256 256K serial EEPROM the WEL bit never gets set. I have checked all of the voltages and have confirmed that the CS line is correct. The 25LC640 gets the correct WEL status bit set on the first try. After a few thousand tries the 25LC256 never sets the bit. The status register always reead zzero. So I know that code protect is not set. I have WP set high so all bytes should be writeable.
The only differences I see between these chips is that the pages size is 64 bytes on the 25LC256 vs 32 bytes on the 25LC640. Also the 25LC256 over all is faster in responses.
So I'm thinking that if it is working with the 25LC640 then there should be no problems with the 25LC256.
I have posted on the Microchip forums also but not getting any responses.
Does anyone have any experience with this chip or have any suggestions.
Thank you.
The PIN_C7 is the one where this chip is being selected.
| Code: |
void Poll_EE_WEL(int1 external) //Wait for Write Enable Latch
{
int16 tries;
int8 st;
do
{
if(!external)
output_low(PIN_C2); //Internal EEPROM CS
else
output_low(PIN_C7); //Eternal EEPROM CS
spi_write(RDSR);
st = spi_read(0);
output_high(PIN_C2);
output_high(PIN_C7);
//LCD_SetCursor(0,14,NORMAL);
//printf(LCD_putc,"STATUS: %u, %lu", st,tries++);
} while((st & 0x02)==0);
}
void Poll_EE(int1 external) //Wait for Write to finish
{
int8 st;
do
{
if(!external)
output_low(PIN_C2); //Internal EEPROM CS
else
output_low(PIN_C7); //Eternal EEPROM CS
spi_write(RDSR);
st = spi_read(0);
output_high(PIN_C2);
output_high(PIN_C7);
} while(st & 0x01);
}
void LoadStepFromEE(int8 program, int8 step, int1 external)
{
int16 address;
int8 lsb, msb, i;
output_high(PIN_C2);
output_high(PIN_C7);
Poll_EE(external);
address = (int16)program * MAX_STEPS * STEP_SIZE;
address += (int16)(step - 1) * STEP_SIZE;
lsb = address & 0xFF;
msb = address >> 8;
if(!external)
output_low(PIN_C2); //Internal EEPROM CS
else
output_low(PIN_C7); //External EEPROM CS
spi_write(READ_SPI);
spi_write(msb);
spi_write(lsb);
for(i=0; i<24; i++)
StepPtr[i] = spi_read(0);
output_high(PIN_C2);
output_high(PIN_C7);
_stepModified = 0;
}
int1 SaveStepToEE(int8 program, int8 step, int1 external)
{
int16 address;
int8 lsb, msb, i;
int1 fail;
output_high(PIN_C2);
output_high(PIN_C7);
Poll_EE(external); //Wait for WIP to clear
address = (int16)program* MAX_STEPS * STEP_SIZE;
address += (int16)(step-1) * STEP_SIZE;
lsb = address & 0xFF;
msb = address >> 8;
if(!external)
output_low(PIN_C2);
else
output_low(PIN_C7);
spi_write(WREN);
output_high(PIN_C2);
output_high(PIN_C7);
NOP
------->>> Poll_EE_WEL(external); //Hangs here
if(!external)
output_low(PIN_C2);
else
output_low(PIN_C7);
spi_write(WRITE_SPI);
spi_write(msb);
spi_write(lsb);
for(i=0; i<24; i++)
spi_write(StepPtr[i]);
output_high(PIN_C2);
output_high(PIN_C7);
//Verify the data was written if we are transferring to external memory
if(external) {
StepPtrSave = StepPtr;
StepPtr = &StepVerify;
LoadStepFromEE(program, step, external); //Load the step just saved into the StepVerify structure;
StepPtr = StepPtrSave; //Restore the old pointer
fail = FALSE;
for(i=0; i<24; i++)
if(StepPtr[i] != VerifyStepPtr[i])
fail = TRUE;
if(fail) {
LCD_SetCursor(0,12,NORMAL);
printf(LCD_putc, "TRANSFER FAILED ");
return FALSE;
}
else {
_stepModified = 0;
}
}
return TRUE;
}
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Last edited by epideath on Mon Sep 11, 2006 12:08 pm; edited 1 time in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Sep 11, 2006 11:26 am |
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Some of your code did not post correctly.
Please edit your post and delete the code. Then re-post it, except
this time select the checkbox below the posting that says:
| Code: | | X Disable HTML in this post |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Sep 11, 2006 11:50 pm |
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Can you post a test program that calls these functions ?
Show the #include PIC statement, #fuses, #use delay(), etc.
Show the #define statements for all constants.
Show your setup_spi() statement.
Post everything necessary so that it can be pasted into an MPLAB
project and it will compile with no errors.
Also post your compiler version. |
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