Hardware · Umbrella
Umbrela is PAL10H8 / HAL10H8 replacement for Toastrack or grey +2 by P0ke^Patisoners. He detailed the function of this IC and developed new version with fixed ULA raining bug, crash while reading $7FFD port, and uncontended ports.
How to:
- remove the old PAL / HAL chip
- solder socket instead
- connect CPU pin no.28 (/RFSH) with socket pin no.11
- burn GAL and put it into socket
.files.
- GAL content: umbrella.zip
.48k.hack.
ZX Spectrum 48k also suffers from an ULA raining bug. It can be solved too, but as there is no PAL/HAL chip, you have to made siple hardware hack. The principle is the same as on the 128k models. You need to fix A14 and A15 behavior with /RFSH signal. So cut A14 and A15 betwen CPU and ULA, and put this simple logic there:
