Apple-1 BASIC Firmware Card

Another EUREKA moment... well, sort of...

I spent some time over the last few weeks building an expansion card with Apple-1 BASIC programmed on an EPROM. I am able to see the code starting at address $E000. I had initially included a 7404 inverter on the card (as in the picture) but it is not needed and the wiring has all been disconnected and the chip removed. I will post details on how I built this card soon... I am still trying to get BASIC to actually run.

After a little more research it looks like I'm going to be adding a 7410 3 input NAND gate, so that I can AND and invert VMA * clock(00) * J3 pin 11 and the output will be connected to /CE on the EPROM. When all 3 inputs are active HIGH, the output will be LOW, thus activating EPROM.

UPDATE Feb/3/2010: After looking at the schematics again, I guess I don't need to add any gates.

I have been trying to get BASIC to run using the following commands without any luck:

Start system

Clear screen, Reset

enter: E000R

output: E000: 4C@

At this point, I can't do anything except for a reset. No keyboard input is accepted.

4C is the first byte of BASIC. I should be getting the ">" prompt according to the manual.

=====

I also tried the following:

Start system

Clear screen, Reset

enter: E000.E000R

wait until the "\" appears (as stated in the manual when loading from cassette)

output afterwards, these are the last 3 bytes I see, plus the cursor: E_\@

enter: E000R

output: E000: 4C@