This repository contains firmware files for the Apple-1 Serial Interface expansion card.
## Description
This project aims to provide alternative to the ACI for the Apple-1 replica or original boards owners via use of the serial communication (9600/8-N-1).
The project is based around ATMega328P MCU which operates as half-duplex UART.
# Memory map
| address | function |
| --- | --- |
| `$C100` | the original ACI loader program adapted to the A1SI |
| `$C300` | "teletype on apple-1" test program - the data from remote terminal appears on Apple-1 screen |
| `$C400` | "teletype on remote" test program - the data from Apple-1 appears on remote terminal |
| `$C500` | 0-255 repeating counter - all possible bytes are repeatedly sent to remote terminal |
| `$C600` | serialmonitor - the well known Woz Monitor, but now you type on the remote terminal |
entries for programmers:
| address | function |
| --- | --- |
| `$C000` | ready flag - contains 0x00 if the device is ready to write/read byte |
| `$C080` | read address - the location for data read from the interface, first read of this address switches the device to read mode |
| `$C081` | write address - the location for data to be written via the interface, first write to this address switches the device to read mode |