BigDumbDinosaur wrote:
jbaum81 wrote:
I built a 65c02 based computer and I'm attempting to use the SC28L92...
My POC V1.1 unit, which is equipped with a 28L92, will run at 14 MHz without wait-stating. For that reason, and especially since you are using the 65C02 (you didn't indicate who manufactured your 65C02), I suspect your problem is not with the DUART itself.
Rather than dilute this topic with general hardware stuff, may I suggest you start a new topic for your project in the Hardware subforum? Give it a suitable title, describe the problem in as much detail as you can and above all, post a clear schematic of the entire unit, preferably in monochrome. We can read your schematic and perhaps give you some guidance.
There are some "gotchas" involving the 28L92 and indexed reads/writes with the 65C02. You may have fallen victim to one of them. Ergo it might be helpful to post some source code of your DUART initialization routine, plus the interrupt service routine that handles the DUART. It's better if source code is posted in text files, rather than embedded in your forum post. You can upload and attach files to your post, which is convenient.Thank you so much for the fast response BDD, I'll work on gathering up these materials and will post. In the interim my 65c02 is a new WDC IC.
EDIT:
Never underestimate the power of decoupling caps, even though I have a tons of them all over my board near the IC's, I didn't have any on my breadboard that I'm using to build the circuit for the 28L92. As soon as I added some caps my communications cleaned right up and the serial is stable at 12Mhz, I do still have some stability issues with the system at 12mhz but that may be something else. I'll post in a new thread.
As an aside, the 28L92 is a nice chip, So many options with the registers and it works very well.
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