From 53db541f6058181b7fb18f27e199cbf7b8bef071 Mon Sep 17 00:00:00 2001 From: mahjongg2 Date: Sun, 18 Oct 2020 20:23:14 +0200 Subject: [PATCH] Update README.md --- README.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/README.md b/README.md index e904086..6a7ebba 100644 --- a/README.md +++ b/README.md @@ -18,3 +18,7 @@ ZX81+38rev1,5.zip contains all gerber and drill files for the working updated an The file ZX81+38rev1,5.pdf is the schematic of the corrected revision 1.5 (in black and white) And I will upload kiCad files after I know revision 1.5 is working well. + +We found one more error, that I will fix in revision 1,6: +the keyboard matrix is connected to eigh Address lines, A8 to A15, but the error is that for A8 the version is used that comes from the signal line passing through a 10K resistor (R1) so it is signal A8' , that is not correct, the keyboard needs unattenuated signals, so A8, not A8'. otherwise the resulting dataline does not go low enough to register as "low". +