Gregory's Server|
25 comments
 this is an indirect jump to the console output routine. it's supposed to beep. but it's jumping to 0000! on initial boot, A600 etc is supposed to alias to 8F80 which is in ROM. the jump table is getting copied into the 6532 RIOT but the write is getting corrupted. it's supposed to be '89' but something else is trying to drive the bus at the same time thanks to the magic of the 16822 logic analyzer trigger output, I can see that the 6532's R/W# never gets driven low.  @tubetime  @tubetime If I had enough $, I'd design a Super-RIIOT IC (SPI Ultra Precision Extra ROM ROM I2C I/O Timer... acronym needs work) sure enough, bad inverter. looks like it was bad back in the day--someone removed the MM to 45 jumper. @tubetime What would've been the purpose of the MM to 45 jumper then? @sergioaguayogr the memory in the 6532 is used as a vector table. it's nice to protect it from accidental modification by a runaway program, so MM to 45 is a write protect function. woot! |
@tubetime i see the code