Store Custom Characters for LCD in EEPROM?

[HenrikOlsson]

Hi Chris,
Remember that the CGRAM in the display controller is limited to 64 bytes (if we're talking HD44780) so even if you store 50 custom characters in your EEPROM I don't think you can display more than 8 of them simultaneously. Perhaps it's possible to load a character to the CGRAM, "print it" and then load another character to CGRAM replacing the first one without it automatically being replaced on the actual display. I don't know for sure, just something to think about.

Anyway, the DATA directive/command is used to embedd EEPROM data in the .hex file so that the EEPROM is programmed at the same time as the program flash (as long as the device programmer is setup to "program EEPROM"). READ is then used to retrieve the data from the EEPROM. WRITE is used to write to the EEPROM at runtime.

/Henrik.

[CuriousOne]

There were early implementations of these display modules, where discrete ICs were used, and charset was in separate mask rom. It was possible to replace such rom chip with own chip, with all custom chars in it. I haven't seen such module live maybe for last 15 years or so.