[avr-chat] EEprom functions on Tiny13

[Robert von Knobloch]

I am using a Tiny 13 in a control application and have written all my
code in assembler.
Because we want to do some clever(er) things with it, I decided to
recode it in C (the application is small enough that it fits).
I have struggled to get a piece of code running that reads the eeprom
using a pointer.

Code like    "x = eeprom_read_byte(&eevalue)" appears to work,
but    "uint8_t * ptr; x=eeprom_read_byte(ptr)" does not.

It appears to be a problem in that these functions pass a 16-bit address
to the asm call for the function, whreas the hardware only supports an
8-bit address (I conclude).
Why the read of "&var" works and the pointer doesn't - I do not know.

I have re-written the function using direct 'bit-twiddling' on the
hardware and this works fine.

Has anyone else had similar experiences?? Is it perhaps a bug in the
library (said quietly), or have I misunderstood the function??

Best regards,

Robert von Knobloch