OT: Arduino Micro

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Jim McClanahan

Mar 11, 2023, 3:01:43 PMMar 11
to PAL 6502 computer
This is a bit off topic, but something I've found really interesting. I picked up a clone of the Sparkfun Pro Micro which is a fancied up Arduino Micro. It was around $15 for a pair of them. I bought it to build a "mouse jiggler" (it can look like an HID on the USB port, so you can emulate a mouse or keyboard).


With a simple program (less than a dozen lines of code), this could act as a TTL level (it can work at either 5 or 3.3 volts) serial to USB interface. It has 12 other digital I/O pins and supports SPI and I2C.

If you did use it as a serial to USB converter, it seems like it should be possible to intercept the serial stream and do something with it. Without some type of off-board storage, it would be limited, but with an EEPROM connected to the SPI interface it seems like you could potentially have a few images that would load into RAM. In theory, you could also use some of the outputs to automate things like switching on the on-board keyboard and LEDs or switching ROM banks.

The fact that you can get something that adds a reasonable amount of processing power (by 1980s standards) in the "serial interface" for a few dollars is pretty cool. I need to spend some time learning more about SPI to figure out how usable that would be.


GN Liu

Mar 12, 2023, 4:51:28 AMMar 12
to PAL 6502 computer
I think it can act as some kind of modern peripheral protocol converter for 8-bit machines, like a SD card driver.


Jim McClanahan

Mar 12, 2023, 9:29:13 AMMar 12
to GN Liu, PAL 6502 computer
There is a board called the Teensy that is more expensive (around $30), but has an ARM running at 600 MHz and a onboard microcontroller to offload some of the I/O work. It has an SD card jack onboard, can support Ethernet, and does just about anything you could want. I have on that is running RunCPM which makes it look like a fairly powerful CP/M machine (all in the footprint of a normal CPU chip). The downside is that it runs at 3.3 volts. Interfacing something like that to RIOT #2 could open up a lot of possibilities.


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Jeremy Starcher

Mar 12, 2023, 10:18:51 AMMar 12
to PAL 6502 computer
There is a lo you could do to interface an Arduino to a KIM-1/PAL-1, some of which I have the hardware here for and was on my `todo` list.

I have a macro keyboard and LCD touch screen that I could load on my 16 most common used PAL-1 software and upload it via the serial line (much cheaper than the wonderful DRT, but a bit slower.)

Make a complete dumb term/glass tty.  Emitting VGA from the various microcontroller isn't difficult and reading AT keyboards is fairly easy.  For extra fun, design your own retro-keyboard with just the keys of the era.

If you want to tinker, there is a 100Mhz MOS 6502 drop-in replacement running off a teensie -- boost your PAL-1 speeds.
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