HI Alan,
Yes, that is true, some are really good - SAME70 will work that way but no
USB. And yes, MEMS is not there yet.
In this case, my BOM was wrong - X1 DNP - so I got enough running to make
progress anyhow (tested a lot of HW).
The most interesting aspect of this F103 finding for me is that
I don't know how ST internal oscillator is implemented in silicon, but
some MCUs have good internal oscillator.
For example the SAMD21 used on Arduino M0 board works fine with NSH
running at 115200 and it even supports USB console, but I didn't test
your freezing spray, maybe it could fail too. :-
Hi David,
Wow. That is precisely what is wrong, you can get yourself a little TRIM
and make one of the boards work, but
then you would have to hand tune them +/- 1% for every baud rate and worse,
temperatures. So better to pay the 71
cents and put the 8M crystal on the board. For testing I used co
HSI is not a good choice if there are external interfaces. It can vary too
much part to part and over temperature to meet the 2% across the system
boundary. They claim 1% @25c but that is 1/2 the budget to begin with,
https://www.st.com/resource/en/application_note/dm00425536-how-to-optimize-stm32
Anyone ever use the HSI on STM32F103, how about RET6? I know the code is
set up for HSE. I got it working, at least UART1.
But now, the other usart devices ... Wondering if anyone has ever run into
UART baud rate mismatches on using HSI? I have a few
radios that work great with an existing driver a
