Generic SCART adapter for TTL/EF9345 display device

3 in 1 project breakable board

Notes :

• This project have never been built from OSHW, it may contain some mistakes, and no improvement is planned.
• The Power/Video board substitute was only built and tested on veroboard

1) CGA/MDA/PET TTL brownfix adapter

[Won't adjust MDA/PET syncs to 15Khz ...]

Board to select TTL inputs for C128 (80 cols), PET

• DB9 : TTL input
• U2 to manage Sync polarity
• U7 to manage brown fix
• J2 : Select sync polarity and filter TTL colors
• J3 : Enable/Disable Brown Fix
• J4 : Enable/Disable HVsync reverse
• J5 : Select color for TTL mono
• J6 : Select mode for mono input (TTL /or video)
• J7 : Force color ground (in conjunction to color of TTL mono)

2) Power/Video board substitute

1. M1b RTIC power board replacement

   - Provides reset signal to main CPU board

   - Provides +5V power to main CPU board

   - Optionnaly, provides +12V power to main CPU board (needed for line relay and peri-informatique power supply)

   - Optionally, provides negative power to main CPU (needed for modem usage)

    

    

   Usage : 

   Direct connection of the 8 wires cable

   - No need of power supply on peri-informatique (DIN5) plug and +5V regulated available ==> Provide +5V regulated (no need of XL4015)

   - No need of power supply on peri-informatique (DIN5) plug but no +5V regulated available ==> Provide +12V (need of XL4015)

   - Need of power supply on peri-informatique (DIN5) or modem relay activation ==> Provide +12V (need of XL4015)

   - Need of modem operation ==> Provide +12V (need of XL4015) and -9V

   - May brake or let the output stage board

    

2. TTL to SCART output stage 

• H5 : Input from EF9345
• H6 : Output to SCRAT
• J8 : Select CSYNC source
• J9 : Select video out source (Mono-in/9345)
• J10 : Select mode for Y ouput (TTL 3v /or video out source)

- Need of 5V power supply if separated from power board

- Need of RGBY signals from EF9345 to H5 header (direct connection with a 4 wires cable to test point #60 of RTIC M1b minitel)

- Need of a SCART cable to H6 header

Usage :

EF9345 outputs are buffered by 74LS244 driver for more safety

Colors output stage is a direct copy of Matra's Alice 32/90 schematics. It fits SCART requirements as well as GBS8200 ones.

Sync output stage is a voltage divider, providing a multiplexed HS and VS signal fiting GBS8220 requirements and acceptable to SCART.