On 12/19/2012 05:55 PM, Rob Clarke wrote: > > Q) When a 6510 is reset, what’s the default state of the DDR and I/O ports? I would be surprised if it wasn't input since that's the only safe state at power up/reset. > The answer I am hoping for is that they are set for input so that I could > have a pull-up resistor on /OE up to disable the latch outputs and rely on > the pull-ups on the address lines to bank in the correct menu image when > RESET. That's about what happens in the C64. There the 3 control lines going from the CPU port to the PLA, _LORAM, _HIRAM and _CHAREN have 3.3KOhm pullups. As for a latch, you might want to take a look at the '273. This one has a _CLEAR input with which you can reset all latches to LOW upon Reset and get your defined state. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2012-12-19 18:00:48
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