OK, so here are the system specs I will at least have in the end, and may get better over time.
|RAM in minimal system||32 KiB|
|maximum RAM||Newer motherboard to support up to 96KiB|
|video resolution||VGA or lower|
|Disk space in minimal system||64 KiB EEPROM|
|main system clock speed||4 MHz|
This is the
third fourth attempt at getting this thing working, and it seems to be getting easier and cheaper over time. I think this time I'll get it right. Things on the board do quite a bit already, because there aren't really any errors in the PCB (I need a new motherboard...)
CPU clock speed auto adjust
The RAM I am using is BLAZING fast. Not very retro, but whatever. The EEPROM, however is very slow. 150ns. If the EEPROM is deselected, why not go at a faster speed? The CPU I have can handle 20Mhz. New logic in my motherboard (see logs) allows faster speeds, but the other devices can only handle a small boost. I am going to cap the speed at 8MHz for now, assuming EEPROM is unused.
I like the concept of motherboards. I'm just used to it from building computers. I have ordered 5 motherboards from easyEDA. RTC is supported, but I when I ordered the RTC chips they sent me the wrong chips! I will work on other stuff for now.