arm configuration memory

Hi

I was not able to find eeprom in atmel and philips arm micros for cofiguration reated memory changeable while application is running. Do i have to use external eeprom for that or is there way to use internal flash for example via let say IAP in nxp processors ?
Please post your experience.

thanks

I suggest to use external EEPROM.
1. The flash in the NXP's ARM based MCU, only 100K erase/write cycles and 20 years of data retention.
EEPROM has 1M erase/write cycles and 200 years of data retention.
2. IAP only offers "Copy RAM to Flash" within 256 byte boundary. (depends on chip)
And the size of written should be 256/512/1K/4K (depends on chip)
You have to prepare the bulk data in RAM first.
3. the Flash memory must erase before writing. (of course, 1->0 is OK without erasing)
And the erase is based on Sector, the size of sector will be 4K or more (depends on chip)

So the internal flash memory is not suitable for small frequent changable data.
FYR.

Yes, that sounds reasonable and i included eeprom yesterday into design to make sure that it wont depend of flash issues. if not wrong at91sam allows only 10K writes.

eeprom seems the only missed part compared to avr micros , but it makes difference only for 1 dollar or less.

artem said:

eeprom seems the only missed part compared to avr micros , but it makes difference only for 1 dollar or less.

Click to expand...

Well I would assume that the internal oscillator, the low power down current, small packages and a few more things are missing. Nevertheless going from AVR to ARM is definitely a step forward in performance and your orientation for the future.

There is a EEPROM "simulation" application note for the NXP LPC2000 family but I would recommend to use an external EEPROM as you said you are planning now. For large quantities te $1 difference is important, for small quantities it is not worth the hazzle using the internal Flash to simulate EEPROM because you always have to write in 16 bytes chunks. On the other hand the NXP micros offer low cost chips up to 512k Flash and it probably does not hurt to use 16k out of 512 to simulate EEPROM if you need to keep cost low.

Bob