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-mcus-internal-rc-oscillator-accuracy-stmicroelectronics.pdf On Tue, Aug 23, 2022 at 2:10 AM James Dougherty <jafr...@gmail.com> wrote: > 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 and a diff design, but not > joy on the F103RET6. I am using internal PLL, x8 (64Mhz) > and 32Mhz (APB1, APB2) if anyone has any debug pointers that would be > great. Its weird, the UART1 uses APB2, and others > use APB1. I know I need the external crystal but I got these boards and no > clock stuffed... (sigh) > > thanks! > -james >
