Now with 128K

That's right - our spectrum has got an upgrade!

I’ve been busy getting things sorted with Crowd Supply - we’re almost live, but in the meantime, you can register your interest here.

I’ve been testing the lasted boards from PCBWay there are some notable updates. I’m now using a proper power control IC to switch between the USB 5v and the battery.

There’s a couple of reasons for this - the main one is that has automatic control of inrush current. There’s an interesting little bit in the USB spec that says you are only allowed a maximum of 10uF capacitance on the power lines. With all our decoupling capacitors, and some bulk capacitance, we are now way over that. This nice little IC will limit the current when we’re first plugged in so it appears that our capacitance is much lower.

The other big change to the board is that we've upgraded the speaker. We did have a 0.7W speaker on the board. This was more than sufficient for the old 48K buzzer, but struggled playing richer sounds.

Which leads nicely onto the biggest update - we’ve now got support for the 128K ZX Spectrum - this includes emulation of the AY sound chip.

You can hear it in all it’s glory in this video:

While I was messing around with the firmware, I took the chance to port over my video player.

I also had a go porting over retro-go - this turned out to be pretty painless - so yes, we can actually run DOOM on our board :)