From 0434ae5047b8e64ce188361ca8267d95c86e6c9d Mon Sep 17 00:00:00 2001 From: Kelly Fox Date: Thu, 29 Oct 2026 20:33:01 -0500 Subject: [PATCH] tools: the bench README warns off DMA while GEOS 128 runs in 80 columns --- tools/bench/README.md | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/bench/README.md b/tools/bench/README.md index c2e9785d..167c7e1b 100644 --- a/tools/bench/README.md +++ b/tools/bench/README.md @@ -34,6 +34,12 @@ whatever node appeared beside it. `peek`, `poke` and everything built on them (`screen`, `keypress`, `colors`, `fwupdate`'s prompt answering) use DMA and need a Fab 0.4 board (a TR+). +Do not use them on a C128 running GEOS 128 in 80 columns: a single one-byte +`peek.py` stops it, clock and mouse both, until a reset. That mode runs the 8502 +at 2 MHz, which is the likely cause but has not been isolated. GEOS 64 on the +same C128 survives peeks and whole-bitmap reads. Check an 80-column screen with +a capture device instead. + ## Scripts | Script | Does |