#avr Logs

Apr 23 2022

12:00 AM nonlinear is now known as zero-xray
08:33 AM specing_ is now known as specing
01:20 PM LeoNerd: I'm sure I remember reading an article from Microchip, on the AVR 1-series tiny chips, about improving accuracy of the main 20MHz CPU oscillator by comparing it to the RTC and nudging the calibration register around... But for much searching about, I can't seem to find it currently
01:20 PM LeoNerd: Does anyone know of such a document?
03:19 PM bpye2 is now known as bpye
04:22 PM bpye4 is now known as bpye
04:25 PM LeoNerd: Ugh.. Yet more poking around at the chip today, and I can't get something working. Eventually it turns out to be a "known bug" on the errata page - https://github.com/SpenceKonde/megaTinyCore/blob/master/megaavr/extras/Errata.md
04:25 PM LeoNerd: Bug is: TCB doesn't work in freq+duty capture mode, with prescaler.
04:25 PM LeoNerd: Which sucks. Without a prescaler, you're very limited in the frequency range you can work with
04:29 PM qu1j0t3: LeoNerd: x_x
04:33 PM LeoNerd: It also doesn't have an overflow interrupt at all, so.. no way to detect overflow of the timer when in capture mode
04:34 PM LeoNerd: This is not a great timer :/
04:34 PM qu1j0t3: 2/10 would not fab again
04:37 PM LeoNerd: Ahah, but in plain freq mode without pulsewidth, it -does- work with the prescaler
04:42 PM LeoNerd: OK so I guess I need to split my code in two; alternate between frequency and pulsewidth.. or maybe use both TCB units, one to do each
05:17 PM LeoNerd: Heh. So, the TCB unit in the newer AVR32DA32 chips has an OVF interrupt, and there's more than one of the TCB units there. You can cascade two of them together, by using the events system to route the OVF interrupt of the LSB counter into the count input of the MSB counter. Great. It calls that "32bit capture" mode
05:17 PM LeoNerd: The tiny1616 datasheet has a single line in the overview of TCB where it says 32bit capture. That datasheet says nothing more on the subject
06:08 PM rue_mohr: anyone tried avr cores for FPGAs?
08:33 PM specing_ is now known as specing