My initial attempts to write to the FRAM used SX/B commands like SHIFTIN and SHIFTOUT. These operated at a slow rate of about 83kbits/s. It did work and functioned as a good test of the hardware setup.
Now that I’m convinced everything is physically hooked up ok, soldered ok, etc, I’ve moved to assembly.
I wrote read/write routines which basically mimic the functionality of SHIFTIN/SHIFTOUT at a much higher datarate. I’m running in excess of 7mbps. That’s one bit every 142ns, or a byte in 1.1us.
I’ve tested my code segments today with the FRAM, and they are working like a charm. The code worked off the written page minus me forgetting the difference between JNZ and JZ. I actually had to step through the code to figure this out. Ahh well, easy enough. It took me 30 minutes to get the code running.
The next step is to plug this into one of my working models, probably the one that measures the time between the edges because I’ll have 4us minimum to work with. This model requires a little extra time, upwards of 1us or so, but I’ll still have 3us left over to store the data. Plenty.
Also, I have to integrate the USB code into the model as well.
Lots to do, and I want to put up a progress meter which shows the progress/task list.