From 5bee9be8b8a9c19e1ad6143e275e640fcb6ce5ca Mon Sep 17 00:00:00 2001 From: s3lph Date: Mon, 7 Feb 2022 09:48:40 +0100 Subject: [PATCH] Update readme --- README.md | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/README.md b/README.md index 04ad220..233a201 100644 --- a/README.md +++ b/README.md @@ -26,9 +26,9 @@ patterns. * Install the [xa65][xa65] toolchain. * Clone this repository. * Run `make`. This will produce (among other) the following files: - * `memtest-f000.901465.bin`: The binary you'll later flash to an ((E)E)PROM. - * `memtest-f000.901465+ascii.bin`: The same code, but text is rendered as ASCII instead of PETSCII. Used by the emulator. - * `emu6502`: A MOS 6502 emulator for testing. + * `memtest*k-f000.901465.bin`: 4K, 8K, 16K and 32K variants of the binary you'll later flash to an ((E)E)PROM. + * `out/memtest4k-f000-ascii.emu6502.bin`: The same code, but text is rendered as ASCII instead of PETSCII. Used by the emulator. + * `out/emu6502`: A MOS 6502 emulator for testing. ## Testing in the Emulator @@ -36,7 +36,7 @@ The emulator uses [Fake6502][fake6502] to emulate the MOS 6502 CPU. The following memory regions are mapped into the emulator's address space, compatible with the PET 2001 / CBM 3001 memory map: -* `$0000:$0fff`: RAM with simulated failures (reduced size for faster testing) +* `$0000:$0fff`: RAM with simulated failures (4K only for faster testing) * `$8000:$8fff`: Video buffer, printed to stdout after each instruction * `$f000:$ffff`: The `memtest-f000.901465+ascii.bin` ROM @@ -44,9 +44,10 @@ Run `./emu6502`. ## Run on a Real PET / CBM -* Flash the `memtest-f000.901465.bin` binary to a ((E)E)PROM compatible to the MOS 901465 ROM chip. +* Figure out how much memory your device has. Choose the appropriate image (`memtest4k`, `memtest8k`, `memtest16k` or `memtest32k`). +* Flash the `memtest*k-f000.901465.bin` image to a ((E)E)PROM compatible to the MOS 901465 ROM chip. * Most parallel ROMs of at least 4KiB should be usable, just short the excess uppermost address pins to GND and ensure pin compatibility, e.g. through an adapter PCB. -* Remove the KERNAL ROM from your PET / CBM. +* Remove the KERNAL ROM (the one mapped to `$f000:$ffff`) from your PET / CBM. * Place the memtest ROM into the same socket. * Power up the computer. It should immediately start testing the memory. @@ -63,6 +64,7 @@ After starting up, most of the screen will be empty. * When all memtest passes have completed, there will be an additional `=` character left of these chars. * When the memtest routine was interrupted by an NMI, there will be a `!` instead. * When the screen is not cleared (filled with random characters), and the first line starts with `ZF***ZF` (`*` being other seemingly random characters), a fault in the first few bytes of the zero page were detected. Since the memtest uses this area to store its state, the test is terminated prematurely. + * The tree characters in between the two `ZF`s are, from left to right, the zeropage address byte, the value written, the value read back. ``` ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓