From 69f95e462eac43cad6b10b44595fabd2516b75f6 Mon Sep 17 00:00:00 2001 From: "Curt J. Sampson" Date: Tue, 7 Dec 2021 18:14:08 +0900 Subject: [PATCH 1/2] SBC/README: Fix backwards description of the VP GND jumper Issue #29 from ea4eoz noted that this is backwards for the revision H board. It's clearly must be backwards for _every_ revision, since closing a jumper, rather than opening it, is the way to connect the other side of the jumper to ground. (This error was inserted by me when I originally wrote this section of the documentation.) --- RC6502 Apple 1 SBC/README.md | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/RC6502 Apple 1 SBC/README.md b/RC6502 Apple 1 SBC/README.md index 4892de8..7a50ced 100644 --- a/RC6502 Apple 1 SBC/README.md +++ b/RC6502 Apple 1 SBC/README.md @@ -88,11 +88,9 @@ box around the pins that enable. the expansion bus connector. - `VP GND` - - Shorted: WD65C02 CPU. Leaves pin 1 of the CPU (`V̅P̅` on the - WD65C02) floating. - - Open: Original MOS 6502, UM6502, SY6502, R65C02. Connects pin 1 of - the CPU to ground, providing an additional ground connection for - the CPU. + - Shorted: Original MOS 6502, UM6502, SY6502, R65C02. Connects pin 1 of the + CPU to ground, providing an additional ground connection for the CPU. + - Open: WD65C02 CPU. Leaves pin 1 of the CPU (`V̅P̅` on the WD65C02) floating. - `PIA_EN` - Top pair shorted: Enable PIA. Connects `CS1` to Vcc. From 6b8fa61b8ccb6b62510619545873ddf4cdb81276 Mon Sep 17 00:00:00 2001 From: "Curt J. Sampson" Date: Tue, 7 Dec 2021 18:18:46 +0900 Subject: [PATCH 2/2] SBC/README: RAM_EN jumper is vertical on newer versions of the board Issue #29 from ea4eoz noted this, and I've confirmed myself that the latest revision as of this commit (e395f27) has moved the jumper to a vertical orientation with the lowest pin connected to Vcc. --- RC6502 Apple 1 SBC/README.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/RC6502 Apple 1 SBC/README.md b/RC6502 Apple 1 SBC/README.md index 7a50ced..2b3396f 100644 --- a/RC6502 Apple 1 SBC/README.md +++ b/RC6502 Apple 1 SBC/README.md @@ -97,9 +97,9 @@ box around the pins that enable. - Bottom pair shorted: Disable PIA. Connects `CS1` to ground. - `RAM_EN` - - Left pair shorted: Enable RAM. Connects RAM `C̅S̅`/`O̅E̅` to address + - Left or upper pair shorted: Enable RAM. Connects RAM `C̅S̅`/`O̅E̅` to address decoding logic (`CS_RAM`). - - Right pair shorted: Disable RAM. Connects RAM `C̅S̅`/`O̅E̅` to Vcc. + - Right or lower pair shorted: Disable RAM. Connects RAM `C̅S̅`/`O̅E̅` to Vcc. - `ROM_EN` - Top pair shorted: Enable ROM. Connects ROM `C̅E̅`/`O̅E̅` to address