What are CGROM (Character Generator ROM), CGRAM (Character Generator RAM), DCRAM (Data Control RAM) and ADRAM (Additional Data)?
Descriptive Answer:
CGROM, CGRAM and DCRAM are embedded in 5x7 dot character VFD drivers. General or Custom codes are installed in CGROM. CGRAM can be used for additional characters that would be 5x7 dot characters or graphic characters. Once installed in CGRAM, characters are retained in the system until it is powered off. This is more efficient than getting the characters from another external memory every time it is needed. However, the characters have to be re-installed each time the system is powered-up. DCRAM works as an address pointer to character data in CGROM or CGRAM. ADRAM stores a symbol data and can be used for a cursor on display.
