6 ms·

I've actually had quite a bit of motivation after moving out of my old apartment. I was able to unpack all of my electronics stuff and tools again. Previous pla

I've actually had quite a bit of motivation after moving out of my old apartment. I was able to unpack all of my electronics stuff and tools again. Previous place was way too small. Actually unpacking stuff triggered a lot of desire to do stuff with it again. One of the things I found was a tube full of rom-less 8051 microcontrollers and another tube of AM85C30 Dual UARTs I probably picked up at a robotics club swap meet years ago. Ended up building a breadboard "computer" and picked up an universal programmer on eBay for like $50 (uses the open source minipro tool). (https://imgur.com/IjJ6HO6 https://imgur.com/IjJ6HO6) Also did some reverse engineering on how to do in-system programming of the BIOS chip in some 386EX based single board computer I have. I wanted to give myself an extra challenge while following the rust blog_os project.

myself248 6y ago
You need some "magic baud" crystals! I'm partial to 11.0592 because it fits nicely under chips rated for 12MHz without wasting much, and a lot of parts rated for 10 will happily overclock there quite stably. This is an incredibly useful reference: https://en.wikipedia.org/wiki/Crystal_oscillator_frequencies https://en.wikipedia.org/wiki/Crystal_oscillator_frequencies
- Teknoman117 6y ago
  Yup! I have some on hand, but the DUART only takes a single clock line and I didn't have the parts for to build the crystal driver. This particular 8051 has a built in one, but no oscillator out. Was contemplating using one of its timers. I didn't even realize the AVR supported a clock out until I bumped into it in the data sheet. Maddeningly it's not broken out on the Arduno Mega =P.
raducu 6y ago
I'm in the same boat -- too little space for my electronics hobby. I did buy an 200 mhz osciloscope, soldering microscope, hot air and new soldering iron though. The only excuse to pull them out is to fix broken electronics/toys.

myself248 6y ago

You need some "magic baud" crystals! I'm partial to 11.0592 because it fits nicely under chips rated for 12MHz without wasting much, and a lot of parts rated for 10 will happily overclock there quite stably. This is an incredibly useful reference: https://en.wikipedia.org/wiki/Crystal_oscillator_frequencies https://en.wikipedia.org/wiki/Crystal_oscillator_frequencies

Teknoman117 6y ago
Yup! I have some on hand, but the DUART only takes a single clock line and I didn't have the parts for to build the crystal driver. This particular 8051 has a built in one, but no oscillator out. Was contemplating using one of its timers. I didn't even realize the AVR supported a clock out until I bumped into it in the data sheet. Maddeningly it's not broken out on the Arduno Mega =P.

raducu 6y ago

I'm in the same boat -- too little space for my electronics hobby. I did buy an 200 mhz osciloscope, soldering microscope, hot air and new soldering iron though. The only excuse to pull them out is to fix broken electronics/toys.