Yeah, that’s basically doing it in HW from RAM – doesn’t even need the CPU 🙂

Uses some different techniques and could be modified for parallel load from an address, rather than using serial data from a USART, it does require a few more IC’s though – counter, gates and shift register at the minimum.

I’ll look into the clock sync suggestion thank you! Meanwhile I just today shared my project with the Acorn community. I include full credit to yours and many others that have helped me with this fun project. Thank you again and happy holidays! https://stardot.org.uk/forums/viewtopic.php?f=3&t=26047&p=379144#p379144

I’m happy you got it working! You might be having issues with the 8Mhz clock not being sync’d with the 1MHz clock so it sometimes shifts too fast/slow?
I could probably improve the circuit quite a bit but it sounds like you’re way ahead of me.

So I managed to get it working by running CB1 through another inverter to have the pulse to SH/LD (Pin 1) latch the data when the CB2 data signal is present. I am seeing so odd artifacts when I toggle lights off and some remain on. – but i think thats a problem. Onwards and upwards!

Me again! 🙂 I am hooking this circuit (with added 8MHZ crystal) up to my Beeb and have partial results. I can control a number of LEDs.

However on closer inspection the data signal to LED matrix is missing the first bit of each byte sent via CB2, it sends a 0 and then only the first 7 bits from CB2 are being sent. Looking at it through my scope I can see that the small pulse sent to the PL pin is being sent to soon before data on CB2 starts to be sent. Afterwards due to timing the second pulse picks up the tail end of the first bit of data from CB2, but by this time the circuit has of course sent 1 of 8 bits.

When I look at the data sheet for mode 110 it does show this as well. The odd thing is on the Ben Eater system above it worked fine (I plan to do more compares at the weekend with my scope). Meanwhile any thoughts on this?

Well done! 😀

Sorry wrong link – this works – https://www.reddit.com/r/beneater/comments/wd6irw/ben_eater_6502_computer_driving_ws2812b_rgb_leds/?utm_source=share&utm_medium=ios_app&utm_name=iossmf

I built Ben Eaters breadboard computer and thought I would first try to integrate with that. Success! https://www.reddit.com/r/beneater/comments/wd6enp/ben_eater_6502_computer_driving_ws2812b_rgb_led/?utm_source=share&utm_medium=ios_app&utm_name=iossmf

Thank you! Schematic is already included in the post – no board files, just threw it on a veroboard.
The ‘Beeb would probably need a few more modifications than this, since it – afaik – doesn’t have an 8 Mhz synchronized clock available. Maybe a separate 8 Mhz clock could be used and sync’ed with a 74×74. The way I did this also depends on CB1 and CB2 being available as a shift register – if not, then a whole parallel port + another external shift register would be needed. Certainly not plug’n’play with the ‘Beeb but not completely impossible to use the same approach – with some extra hardware thrown at it.