Arduino for STM32

cagz wrote: ↑Sat Aug 12, 2023 4:08 pm Can I please ask, where in Arduino IDE you found the build flags ?

In Arduino IDE preferences "show verbose output during compile" and you should see them in the normal output now.

Just an a idea for experiment: Attach interrupt on RW falling, and if DS is low grab data? It would trigger on every write, but writes on 6502 is not so often. As long as ISR is shorter than 4µS, it should be working for latency up to 800, maybe 900nS. Thanks for that. I'm going to see how far I ca...

That code was for Apple 2. OH!! Hahaha, got it yes :D Anyway, by looking at datasheet you posted in first post, i still think you need to experiment and see what timings give you predictable result. Yes totally agree with those timings. It's the bare metal timings on the bluepill that I need to lea...

Try to get CPU at known state, run some simple program... I've never run asm directly in a sketch but I'll look for examples, I've seen it in other people's code. Maybe add some pin toggle as a test for digital analyzer. Good idea, this should be a good exercise and I can use the oscilloscope. Mayb...

Bakisha I tested with both variations. I assume you meant PB_6 (BUS00) not PB_5. while( (GPIOB->IDR) & (1<<6) ) { // output is always 00000000 00000000 00000000 00000000 while(digitalReadFast(PB_6)==LOW){ // output is always 00000000 00000000 01111111 00111000 I double checked the wiring to mak...

@Bakisha I didn't write the displayBits32 function, but I did just test it:
Output: So appears to be working?

I'm going to adjust the sketch with your changes and re-run, I'll post again shortly.

ag123 thanks for bridge chip suggestion! As I understand it PortB is 5V "Tolerant" - does this mean I should have external 5V pull-up's on the pins? Yes, the stm32 is 72x faster than the Apple2, so I'm sure we can read & write easily once the timing & circuitry is sorted :) dannyf...

Bakisha I tried your suggestion. Seems no matter what data I write the output is always: 00000000 00000000 00100000 01011000 Sketch Code: // attach interrupt at falling edge of DS , and while BUS00 is low, keep reading data bus... // output is always 00000000 00000000 00100000 01011000 // Control S...

Just to be sure the machine language code was correct I connected a logic analyzer to the bus for each command and confirmed the data bus is correct: (Edit: the images are hard to read, I put a red circle around the data bus values which match up with the commands) C0E0-00 Apple Bus C0E0-00.jpg C0E0...

I designed an AppleII peripheral card with breakouts for the expansion slot and BluePill as an experimental project to interface the two: CardInSlot.jpg The timing diagram for this type of computer is fairly well known ( see here , page 69,70) WriteToPeripheral.PNG Problem is when the bus is read (G...