On 11/9/2020 7:18 PM, Nate Lawson wrote: > Neat project. What is the CPLD for? Since the design can be switched between IEC and IEEE configurations, the CPLD performs those switches. Other designs used 4066 analog switches, since the IEEE interface ICs 75160 and 75161 both have bidirectional lines, but I'm not a fan of 4066s for digital switching. As well, the CPLD allowed me a way to watch for changes on the "config" line and reset the machine if such a change is seen. The CPLD may also allow an opportunity to "soft" switch from one to the other (tickle some VIA bits while in 1541 mode to switch the unit to IEEE mode and reset, and vice versa). > > If someone were to implement an IEEE interface for the Pi1541, what would be the bare minimum parts of this project needed? I’m thinking just the transceivers, and only if more than one drive was attached. I think you'd need at least 7406's (a few of them, for the 8 bits of data and the various control lines) since I do not believe the RPi IO is 5V tolerant. As well, you'd need level shifters on the input lines, but that's just a bunch of resistors. The only other piece would be the IEEE connector itself, which is not dirt cheap, but not horrid. JimReceived on 2020-11-10 06:00:03
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