pokun
Gun-headed
Posts: 85
Homebrew skills: HuC6280 assembly
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Post by pokun on Nov 5, 2019 13:36:42 GMT
If you make it read from the Zapper too, I'll hack duckhunt and a few new zapper games to run as a nes2pce rom. Interesting idea! It looks like the zapper uses a trigger and detect pins. I could put these to button III and IV. Would that make it work for you? By supporting the Zapper I guess you could also use it to read Famicom and NES Arkanoid paddles, which is cool since I don't think the PC Engine has a real paddle controller? The closest thing might be the Pachinko controller. Unlike the Zapper, the paddle doesn't need to be strobed though. Famicom and NES versions both works the same way, just using different pins I think, which is irrelevant for your adapter anyway.
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Post by bobmoo79 on Aug 9, 2021 11:06:30 GMT
Playing around with how this converter will look. I'm thinking a simple in one side out the other. doublehacker did you get this working? I've just spent a few days in isolation and decided to make a similar adapter using an ATMEGA328P. Everything looks good in the SerialMonitor. It captures NES Serial data and outputs in parallel using the 'PORTD' command but the PC Engine doesn't behave as expected, so I suspect a timing issue. I'm going to get a logic analyzer to see what's going on. It would be great to find out your progress
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Post by dshadoff on Aug 9, 2021 13:28:03 GMT
Are you using a 74HC157 multiplexer on the way back to the PC Engine ? The signals need to switch states (4 signals/4 signals) faster than a ATMEGA328 can.
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Post by bobmoo79 on Aug 27, 2021 7:19:15 GMT
Thanks for your response. When I posted this I was only using the atmega but gave up on that shortly after. I got the code to switch states within 3 micro seconds but it still wasn't behaving correctly.
I then added a 74157 to the output of the atmega and still had no joy.
So what happens now is the atmega gets the button presses from the NES pad correctly and it outputs all 8 button states at the same time spread across PORTB and PORT D. This is updated at every cycle. These are directly wired to the inputs of the 74157. The 74157 is controlled directly by the pc engine, so is connected to select and strobe. It still doesn't work.
By the time I got to this point my enthusiasm was waning so I got on with another project.
I don't really understand why it wouldn't work to be honest. I'll try again with a fresh mind at some later point.
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