lostcarpark
Member
I'm tied up with my current QL keyboard I wrote about elsewhere, but I'm thinking about feasibility of future projects.
I'm wondering would it be possible to build an emulator for an 8-bit micro using nothing but a Teensy 3.1. The computers I'm interested in are the Sinclair ZX81 and Spectrum. Here's a picture for anyone too young to remember:

They both ran off a Z80 processor, which I'd be fairly confident the ARM on the Teensy could easily handle by emulation. There are plenty of open source Z80 emulators out there. Like my QL case project, I'd like to house the emulator in the original case. Handling the keyboard ribbon cables would be even easier than for the QL, as both the ZX81 and Spectrum used a simple 8x5 matrix arrangement.
The one place I see a problem is video output. The ZX81 had a very simple monochrome display with a resolution of 256x192 pixels. The spectrum had a slightly more complex arrangement, with the same resolution, but 8 colours.
Would it be insane to try to drive composite video output from the Teensy's IO ports, or would I need something more complex?
James
I'm wondering would it be possible to build an emulator for an 8-bit micro using nothing but a Teensy 3.1. The computers I'm interested in are the Sinclair ZX81 and Spectrum. Here's a picture for anyone too young to remember:

They both ran off a Z80 processor, which I'd be fairly confident the ARM on the Teensy could easily handle by emulation. There are plenty of open source Z80 emulators out there. Like my QL case project, I'd like to house the emulator in the original case. Handling the keyboard ribbon cables would be even easier than for the QL, as both the ZX81 and Spectrum used a simple 8x5 matrix arrangement.
The one place I see a problem is video output. The ZX81 had a very simple monochrome display with a resolution of 256x192 pixels. The spectrum had a slightly more complex arrangement, with the same resolution, but 8 colours.
Would it be insane to try to drive composite video output from the Teensy's IO ports, or would I need something more complex?
James