Complete noob, failing at getting a basic board working.

[floobydust]

Well, a couple things that I didn't see mentioned, missed or simply adding another comment:

1- As you're using a 32KB EEPROM in place of a 16KB EPROM, you should probably ground the A14 pin of the EEPROM, so it is really only using the lower 16KB. If you're not sure how your EEPROM programming went (upper or lower 16KB), put a jumper so you tie it (A14) to ground or +5V as a select for upper or lower 16KB.

2- As you've also tied the WR line of the EEPROM to the qualified write line from the CPU, it's possible that some code could be writing to the EEPROM and altering it's contents. Again, a jumper to tie the WR line to either the WR signal or +5V ( which would be read-only) would be a good option.

and thinking more, a 3rd.... but hinted to:

3- If you're using Grant's code verbatim, ensure you're also setting the hardware up in the same manner. By default, the RTS line to the DB-9 connector is driven from the UART IRQ signal through an inverter, not by the the actual RTS line. I suggest your change this over, unless you've changed the configuration of the UART.

Beyond the above... you either have a wiring error, bad hardware, incorrectly programmed EEPROM or some noise due to your breadboard layout. Good luck.

[BillO]

floobydust wrote:

3- If you're using Grant's code verbatim, ensure you're also setting the hardware up in the same manner. By default, the RTS line to the DB-9 connector is driven from the UART IRQ signal through an inverter, not by the the actual RTS line. I suggest your change this over, unless you've changed the configuration of the UART.

He won't need an inverter as he is using a CP2102 TTL to USB adapter. But I agree, he should use the /IRQ line as intended by the designer, not the /RTS line.