I am looking at interfacing to a HD44780 LCD display with an STM32VL discovery board. I am aware drivers exist but in the interest of learning I am doing it myself.
I am curious about the interaction between the DDRAM, CGROM and CGRAM. In the HD44780 datasheet an example of writing letters is given:
When I read the datasheet the character information for H (or any predefined letter/symbol) is in the CGROM as 01001000, as seen in the image. However it states that it is writing data to the CGRAM/DDRAM. I understand the CGRAM provides space for user created letters/symbols. So why does it state that we are writing to CGRAM and not accessing CGROM to create the pre-defined letter H which is stored in CGROM? (or any letter for that matter)?
Any help would be greatly appreciated!