240p Test Suite for Genesis: Sega CD diagnostics from cart

This is a huge list of updates, that I hadn't released due to postponing a detailed post on how to use the Genesis/Mega Drive version to diagnose Sega CD consoles that don't boot or have issues. Details are below and downloads are here,

It was brought to my attention that I hadn't released the other fixes it has, and I noticed that I did make internal releases to the closer circle that diagnoses Sega CDs or that has been creating profiles for upscalers, but I never released them to the public since I hadn't written that documentation. I realize that it is better to release them now even without it or I'll keep on holding them.

Before a brief description of the Sega CD tools, here are the recent updates made to the 240p Test Suite:

Graphics and Test Patterns

• Updated Monoscopes: Enhanced monoscopes by Keith provide more precise graphical testing.
• Disappearing Logo Test: A new test by RetroRGB, featuring an additional mode requested by MisterAddons, now aids in controller lag testing.
• Phase Check Pattern: Introduced a pattern by FirebrandX that functions in both 320 and 256 modes for Phase calibration as used ni the RetroTink 4K profiles.
• Sharpness Test: Removed the confusing "smart" option selection.
• Gillian Blinking: Added a blinking effect to Gillian for visual emphasis.
• SMPTE Colors: Updated to better match NTSC standards.
• Patterns Menu: Split into separate color and geometry categories for easier navigation.

Memory and Debugging

• Memory Viewer Enhancements: Added options for ASCII and CRC in the Memory Viewer menu.
• Debug Controls: Made user-available, removing their hidden status for easier access.

Audio Enhancements

• FM Sound Test: Now alternates between channels and includes more notes for a comprehensive sound evaluation.
• Audio Sync Test: Automatically starts for quicker setup.

Help and User Interface

• QR Code Addition: Added QR codes to the help and credits sections for easier access to information.
• PLUGE Warning: An upfront warning is now displayed when using the PLUGE test to prevent misuse.
• Font Update: Implemented a new font, suggested by Pinobatch, improving readability via composite.

Under-the-Hood Improvements

• Z80 Call Simplification: Streamlined Z80 calls for efficiency.
• Horizontal Resolution Check: Improved in the Convergence test.
• Memory Viewer Fixes: Defined proper ranges for more accurate memory viewing.

Sega CD Tools from Cart mode:

These have been used for repairs, and even for Sega CD PCB replacement tests! Thanks to Zaxour, Leo Oliveira and the rest of the people using it that have given ideas and feedback.

You can use the cart version of the 240p Test Suite connected to a Sega CD. Of course the Sega CD version itself version also has some tests, but not as extensive since these can be made without the Sega CD running, or even booting!

They are present under Hardware tests, if a Sega CD is detected it will tell you so, and you can also continue if it hasn't been detected due to damage.

First there's yous BIOS ID and CRC checks. It has the MAME CRCs and there is a tool at github with the list and details, that cam also ID Sega CD BIOS files on its own. This will let you know if the BIOS chip is fine, if the ROM is the one you expect, if it has been documented and dumped and also if this fails you know it is either a faulty chip, or traces/glue logic leading to it.

You can check the communication registers used between the Sega CD and the Genesis:

The Program RAM and Word RAM check will let you know if the RAM chips and banking work OK, the patterns used will help you id bad traces and addresses on either one.

You also have the PCM RAM check, which boots up the Sega CD in mode 1. After that you will be able to test the PCM RAM from the Sega Cd side. If boot up fails, you know where it failed so you can diagnose the faulty unit.

PCM RAM tests allow delays so you don't have values that were in the BUS while writing

And finally, you have Sega CD audio tests that allow you to play back sine wave on teh PCM chip and also test the Sega CD drive for CD-DA playback, tray operation and also Drive version.

Sega CD Specific Updates

• PCM RAM Tests: Added extensive testing for PCM RAM, including Ricoh RF5C164 PCM RAM check from both the Genesis and Sega CD sides.
• RAM Test Improvements: RAM tests now operate in 8 or 16-bit modes, checking per byte or word. Failed values are displayed along with the address.
• Laseractive and PCM Check Adjustments: Enhanced for more accurate testing, with contributions from l_oliveira.
• Drive Version Detection: Now detects and displays the Sega CD Drive Version by reading the TOC of a valid CD.
• CD Playback and Controls: Added basic CD playback during the sound test in Mode 1, along with Open & Close options for Sega CD, depending on the model.
• PCM Test Expansion: Now includes a detailed menu for full memory or per-bank tests, showing the bank and offset within it rather than just a flat address.
• Boot Code Optimization: Initial boot code is now loaded only once from the CD to handle race conditions better.
• CD-DA Playback Fix: Addressed an issue where general case CD-DA playback was causing corruption at certain memory locations.
• File Management Enhancements: Improved handling for finding, reading, and failing to find files on the CD-ROM filesystem.
• Sega CD Calls Cleanup: Refined Sega CD calls to reduce errors.

Thanks for your support, you make this possible.

Artemio