View source for Videonics VCU-1

== Overview: ==
The Videonics VCU-1 is an interesting home video editing solution from 1989 that worked by controlling multiple VCRs and mixing them together.

It's an interesting system for two main reasons

# It's x86 based. The main CPU used is an NEC V40, which is a sort of 8088 clone enhanced with some 80186/80286 instructions. 
# It loads the editing software (DirectED/DirectED Plus) off a VHS tape

== Specifications ==
CPU: NEC V40 at 8MHz

RAM: 256 kilobytes 

NVRAM: 8 kilobytes

Output graphics: 768x480, with overlays using 64 colors

PSU: 21 watts, with 7 watts used by the base unit. 

== Initial program load (pre-VHS) ==
An open question about this system is where the initial BIOS is stored. There's two primary possibilities:

# The Motorola S38FC004PG02 chip. This is a custom ASIC which could be doing any number of things, including acting as a mask ROM.
# The Dallas DS1216-enabled SRAM chip. This chip is built into a socket which contains a rechargable battery, and turns an SRAM chip into a NVRAM. It can only store 8 kilobytes, but it's possible some code is stored there. 

== Modules: ==
The Videonics VCU is designed as a modular unit which can have multiple add-ons stacked under it to add additional functionality.

The manual says the expansion modules are connected through a bus providing 4 video & 4 audio channels, and a 38 kilobit/second serial bus. 

Known modules:

* Source Add-on. This add-on adds support for a serial mouse, 5-pin-din keyboard (AT or XT protocol?), printer, and aux & main edit controls (mini-din-8). 
* S-Video Add-on (official name unknown). This adds a mini-din-8 aux edit control, as well as s-video ports for: aux in, monitor out, main vcr in & main vcr out 

== Archived copies of the VHS-based Software: ==

* [https://archive.org/details/Videonics Videonics DirectED Plus 3.65 (uploaded by diognesthefox)]
* [https://archive.org/details/videonicsgraphicslibrary6pack Videonics Graphics 6-Pack (uploaded by diognesthefox)]
* [https://archive.org/details/videonicsgraphicslibrary1.03 Videonics Graphics Library 1.03 (uploaded by diognesthefox)]

== Twitter threads about the Videonics ==

* [https://twitter.com/Foone/status/1317570788120121344 My pickup & teardown of the initial unit] (October 17th, 2020)
* [https://twitter.com/Foone/status/1319807083353575424 The remote, with teardown (and repurposing into a keyboard)] (October 23rd, 2020)
* [https://twitter.com/Foone/status/1321948802715017218 Second unit pickup] (October 29th, 2020)
* [https://twitter.com/Foone/status/1323821925001428992 Failed attempt at loading the archived DirectED Plus 3.65 software off the internet archive onto the second unit] (November 3rd, 2020)
* [https://twitter.com/Foone/status/1325945997160165376 Third unit pickup, with VHS tape and manual] (November 9th, 2020) 
* [https://twitter.com/Foone/status/1328085198131511297 Videonics Tape testing] (November 15th, 2020)

== Other info ==

* [https://gist.github.com/foone/9d111a2cd2917491b2456a6d33dad984 Infrared remote codes (NEC protocol)]
* [https://www.spaco.org/vcu1faq.htm Pete's VCU-1 FAQ]