Interface code to support Heathkit H-89 using the ESP32 as a file server

The Heathkit H-89 is a 1980 era Z-80 based computer running CP/M or HDOS. The interface hardware provides a bidirectional data port at 0xFC, a ESP32 status port at 0xFD, and a wake-up signal for the ESP32 at port 0x7E.

The ESP32 hosts two webpages. One for over the Air updates and another to manage files stored on a micro SD card. The host network ID and password are stored in non-volatile memory on the ESP32. Files for use by the H-89 can be uploaded and download through the webpage by the ESP32.

A prototype board is currently undergoing testing.

Current project status is in the Status directory.

The command interface between the H-89 and ESP32 is listed below:

Web Features:

• Webpage listing files on micro SD card with ability to upload/download/delete
• Ability to reboot ESP32
• Over The Air updates for firmware

Commands: Implemented

• List Files on the micro SD card
• Debug - simple get four bytes from H89, add 1 to each byte and send them back
• Get file from H89 using Xmodem protocol with CRC
• Send file to ESP32 from H89 using Xmodem protocol with CRC
• Reboot ESP32 by writing to Command port twice
• Get Current ESP32 Status

Under Development

• Read Status of last operation
• Read sectors using Cylinder/Head/Sector (CHS)
• Write Sectors using CHS
• Select disk image using text file name
• Select disk image using file number
• Read sectors using LBA
• Write Sectors using LBA