Gradiente CT80E is wrong in openMSX

By retrocanada76

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15-12-2019, 00:33

Hi, I have a Gradiente CT80E and it does not work the same as implemented in openMSX. Looks like in openMSX it only answers to port 88h but if you look the schematics here: https://www.msxpro.com/hardware/esquemas/ct80net.zip you see that it answers to both 88h and 99h. The CT80NET is the same card with different ROM and a RS-232 interface. The CT80E has these items unpopulated but has the same PCB.
In my CX5M when plugging the CT80E I get all output from the composite video of the cartridge, including the boot screen, screen 0 40 columns (TEXT1), screen 1, 2 and 3 and any game I play on it. The ROM will disable the burst signal and when in 80 column the rom first disables both vdps and then enables the output for the 9938 through port 88h. So the 9938 works in slave mode when using port 99h. Since the interrupt is not connected in this cartridge there is no conflict. I played many games and made a small piece of code to get the color burst and changing the cristal to the 21.447Mhz I get color output.

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By retrocanada76

Champion (472)

retrocanada76's picture

15-12-2019, 00:55

There seems to be some bug for Japanese computers that starts in 32 column mode. Looks like some basic hooks does not get set.

By retrocanada76

Champion (472)

retrocanada76's picture

15-12-2019, 00:59

well easily fixable by adding

to Gradiente_CT-80E.xml