8-bit MicrocontrollersのトピックProblem of EEPROM Write and read

Problem of EEPROM Write and read

JalenZ — Sat, 20 Nov 2010 18:16:05 GMT

Hi all:

The MCU is S08EL16, development tool is CW6.3, use "Full chip simulation"

Please see the attached project file, the questions:

Q1: In the main.c file, I want to read a data from the eeprom, when I read data from the address 0x1700, the return value is 0x33 but not 0x22, why this happend?

Q2: I also want to wrtie a data(0x55) into the address 0x1700 use the function " write_eeprom_byte", but it's not work, why?

Thanks!

Re: Problem of EEPROM Write and read

kef — Sun, 21 Nov 2010 18:52:59 GMT

#define EEPROM_ACCESS(x) *(word *)(x)

Did you use this macro to read from 0x1700? Assigning EEPROM_ACCESS(0x1700) to char variable will give 0x33.

write_eeprom_byte is full of bugs:

FSTAT_FACCERR = 1; Is wrong. This will also write one to FCBEF bit and probably will set again some error bit.

Use FSTAT = FSTAT_FACCERR_MASK;

*(word*)(addr) = data;
S08 eeprom is byte programmable, not word programmable.

In your case EEPROM at 0x1700 is not erased. You should erase it before programming.

FSTAT_FCBEF = 1;

FSTAT_FACCERR = 1;

FSTAT_FPVIOL = 1;

FSTAT_FACCERR = 1;

EEPROM_ACCESS(addr) = data; // Write the data
EEPROM_ACCESS should write byte (*(char*)x).

FSTAT = 0x80; // Clear command buffer empty flag

Don't use "magic constants". FSTAT = FSTAT_FCBEF_MASK; is somewhat self documenting.

Re: Problem of EEPROM Write and read

bigmac — Mon, 22 Nov 2010 21:15:59 GMT

Hello,

Usually FCS does not simulate the programming of flash memory. It would therefore not surprise me if the related EEPROM programming was also not simulated.

I think that you will need to prove this part of your code using the real hardware.

Regards,

Mac