Regression learns from examples.

House size → house price.
Repeated many times.

Patterns don’t come from one data point — they emerge from many.

#manytimes #house #houseprice #timepatterns #datapoint #examples

The key switches I chose for the Datapoint 2200 keyboard required a plate so I made one up. Done as a PCB it’s not cheap but the Matt black finish works really well.

The only issue is that it slightly obstructs a couple of capacitors 🙁

I still need to source the hardware to properly mount it to the keyboard.

#datapoint #datapoint2200

Arcnet - It was a contender

https://makertube.net/w/gvEUq9oHsn4u1brNwQBC43

Arcnet - It was a contender

https://makertube.net/w/9LE8TF3GTsbebcVhJcVTen

Top row numbers can be shifted and keypad numbers can't. Both share an edge detector circuit and multiplexer 'line'. Top row key short to ground whereas keypad key have an SIO (or S10) signal. The keyboard logic board uses an analogue edge detector with 74121 pulse generator.

On the Pico I'm handling this by driving the SIO line low. When a keypress is detected I drive it high. If the keypress is still detectable then it's a top row key. If not then keypad.

#Datapoint2200 #Datapoint #keyboard

The #Datapoint2200 keyboard PCBs have arrived and they look fantastic. Somehow larger than I expected, and very imposing.

#datapoint #ttlcomputer #vintagecomputer #retroconputer #mechanicalkeyboard

I've just pushed a very long overdue update to my Datapoint 2200 repository.

New stuff includes schematics for video, keyboard and keyboard logic.

I've added a fair few LEDs to the processor PCB for most of the main registers, but I need to analyse which other signals deserve to have them.

I also need to add some photos and PCB renders to the readme.

https://github.com/Bread80/Datapoint2200

#Datapoint #Datapoint2200

#Datapoint 2200: I have the memory cards designed and assembled but no memory chips. My plan is to add a 'backpack' board using modern parts.

Each card uses 32x 512 bit shift memory chips. The best modern option is probably 512 bit FIFOs and tie the outputs back to the inputs to recirculate data.

You can get 9-bit or 18-bit wide chips but every bit is read and written together. So you need a multiplexer on each bit to select new data or recirculate.

🧵