About gbm

gbm · 2024-10-21

Section 3.20: "It requires a precise 48 MHz clock that is generated from the internal high-speedexternal clock source"So we have "internal external" clock source. ;)

gbm · 2023-06-16

I found this problem with STM32L476 but I suspect it may be a general STM32 quirk.The manual does not list the minimum and maximum value of UART BRR register. While the minimum value of 0x10 seems to be quite obvious, the maximum correct value in the...

gbm · 2022-12-02

Looks like serious regression from 1.10.1. Steps to reproduce: Select STM32F401 or F411 MCU, Enable FreeRTOS. The generated main() function in main.c file does not contain the section creating the FreeRTOS objects (task, queues, etc.). Instead, the c...

gbm · 2022-10-27

When creating project using Board Selector, Nucleo-C031C6, the incorrect MCU pinout definition is created with two errors: I2C1 is activated and pins are assigned for it and USART1 is initialized using PB6&PB7 instead of USART2 with pins PA2&PA3,whic...

gbm · 2022-04-16

USART baud rate related stuff has a long history of errors in both the STM32 documents and sample code. Looks like in the past 4 years some of the problems were corrected but there are still some strange and incorrect pieces.STM32F10x manual, RM0008 ...

gbm · 2024-12-01

Is Button declared properly, with volatile attribute? Basic button handling in SysTick ISR:https://community.st.com/t5/stm32-mcus-products/external-interrupt-and-button-debounce/m-p/722909No capacitor needed. ;)

gbm · 2024-12-01

No EXTI => just SystTick interrupt (already firing in every project).EXIT => EXTI + SysTick interrupt + (optionally) resistor and capacitor.So why should anyone use EXTI for buttons?

gbm · 2024-12-01

Use DMA for SPI - "fire and forget" is much more efficient than interrupt-driven SPI.

gbm · 2024-12-01

Simple: Do not switch, do not use HAL for EXTI. Any port line, no matter how it's configured used by peripherals, may still be used by EXTI. So, configure the I2C with HAL, then configure it for EXTI without HAL. I have no idea if LL config will work...

gbm · 2024-12-01

The main mistake is the use of EXTI for button sensing. Do it inside SysTick ISR. I shown the solution long time ago - search for it.The only reasonable case for buttons and EXTI is the wakeup from deep sleep modes.

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Errors in UART baud rate sections of Reference Manuals

Re: external interrupt

Re: external interrupt

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Re: external interrupt