diff --git a/README.md b/README.md index 7414c58..4202644 100644 --- a/README.md +++ b/README.md @@ -4,6 +4,9 @@ Easy-to-build minimalistic ZX Spectrum clone. [![photo](images/revB.small.jpg)](images/revB.jpg?raw=true) +[(some random photos)](https://cloud.err200.net/index.php/s/73TR85tYZkMm8Ax?path=%2Fsizif-128) + + Specifications: - CPLD EPM7128SLC84 (128 macrocells) - Z80 3.5 MHz @@ -14,8 +17,21 @@ Specifications: - Intended to build on 9x15 prototyping board, but may be built on manufactured PCB To modify and compile CPLD firmware you need Quartus 13.0sp1. -To modify schematic and pcb you need Kicad 5.1.4 or newer. +To modify schematic and pcb you need Kicad 6 or newer. -Please note the [errata](pcb/rev.A/ERRATA.txt) for rev.A pcb. +### Changelog +* Rev.A - first release. Please note the [errata](pcb/rev.A/ERRATA.txt). +* Rev.B - experimental PCB + * 74HCU04-based tape input + * added power LED + * added reset button + * removed NMI button + * C20 replaced by variable variant to tune PAL color signal +* Rev.C + * 74HCU04-based tape input reverted back to transistor-based + * unused U6 inputs has been grounded + * video circuit has been tuned for best colors + * all pcb tracks are fancy now ;) +* Rev.C1 + * improve tape input sensitivity (thanks to SerOne from zx-pk forum) -[Some photos](https://cloud.err200.net/index.php/s/73TR85tYZkMm8Ax?path=%2Fsizif-128)