From 9102f87635cb832cc1acb33f8eb9eff873dd29b9 Mon Sep 17 00:00:00 2001 From: dfnr2 Date: Fri, 3 Jan 2020 08:41:48 -0600 Subject: [PATCH] Update README.md --- hardware/interface-ascii/README.md | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/hardware/interface-ascii/README.md b/hardware/interface-ascii/README.md index 2839191..aff96a8 100644 --- a/hardware/interface-ascii/README.md +++ b/hardware/interface-ascii/README.md @@ -13,6 +13,14 @@ even slightly simplify the hardware layer of the firmware. Assembly Rendering +## Features +- Parallel or serial output +- Up to 8 configuration settings via an up-to-8 position DIP switch +- Apple 1 and Apple 2 compatible outputs. Other configurations can be supported by + making a custom cable. +- Can decode arbitrary keyboards up 16 rows by 8 columns by making a custom keyboard cable. +- Supports up to 3 keyboard LEDs +- Supports up to 3 "special" host outputs, such as RESET, SCREEN_CLEAR, BREAK, etc. ## Overview - The keyboard rows are driven by a pair of 74LS138 decoders, allowing 4 GPIO @@ -24,6 +32,7 @@ even slightly simplify the hardware layer of the firmware. - One GPIO line is used to control a keyboard LED. - Three of the ISP lines are also used as outputs to controll two more Keyboard LEDs and one more "special" output line. +- The DIP switch is wired into row 15 (last row) of the matrix. - The top two parallel I/O bits can also be configured as UART I/O. This could be used to provide serial output instead or parallel output, to support a bootloader, or even to accept a serial input stream from another computer to