I am currently working with the Kent LCD 9560 and need to store a buffer of “pixels”. Currently I’ve stored that buffer in RAM on an Atmega128i (the chip I need to work with) along with an alphabet. This uses a total of 6 k RAM and to include the other features I need to move this all to ROM. My issue is that I need to change values of the buffer and cannot seem to find a way to do that once I have stored it in ROM. Is there any way to write to ROM during runtime?
you answered the question my friend.
ROM = Read Only Memory
RAM = Random Access Memory
Check if the LCD supports read operations. Read a certain area, modify those pixels, write back to lcd
Thanks for the quick reply. Am I misunderstanding how PROGMEM works then?
As far as I understand, PROGMEM will put data into flash that is ‘constant’. to use it, the system copies it to RAM first then it is available until your local variable containing it is destroyed. Haven’t had a need for it yet so I am only guessing.
No, the running program cannot write to PROGMEM.
You might want to look into an external RAM or EEPROM chip.