mos6507's Blog - new board needed

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After a fair amount of testing it's become clear that there will need to be at least one more revision to the Chimera board before it is ready for primetime. At first Delicon only saw one flaw requiring him to solder a jumper wire across the arm. Then we had the power issue related to SD access. This requires a change to the board layout to handle the larger voltage regulator. Now we have noise issues that are severe enough to cause a visible slowly-rolling bands on my A/V modded 2600, which is cause enough for concern to pursue even more aggressive noise-cancelling measures.

 

Delicon also tested joysticks and paddles hooked up to the expansion ports. Joysticks work no problem, but paddles are getting inconsistent readings even though the ARM has its own dedicated ADC circuitry. This may be a more intractable problem than eliminating the video noise. This is worth the effort to address because if we can get solid ADC readings, the VCS will be able to run much more complicated kernels with analog controls. Right now I only have a single serial adapter. Eventually I hope to show tech demos that demonstrate using various peripherals connected through the expansion ports I posted about in earlier blog entries.

 

After replacing my regulator on Saturday I was able to see the CPLD autoswitching work for the first time. While Delicon still has some finishing touches to do on the CPLD cores, the overall design approach has been validated. The cartridge identifies the banking scheme of the game, and will load and run it on the existing core if it can, else it will reprogram the CPLD while my staller code runs from zero-page, and then break out and into the game without a power-cycle. The programming takes about 8 seconds and my staller has a fixed wait of 11 seconds which I can probably safely shave back.

 

 

 

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