Setting GPIO speed / Drive Strength / Slew Rate for F1

rogerclarkmelbourne / Arduino_STM32

Arduino STM32. Hardware files to support STM32 boards, on Arduino IDE 1.8.x including LeafLabs Maple and other generic STM32F103 boards

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Setting GPIO speed / Drive Strength / Slew Rate for F1 #803

Closed orkunkilinc closed 3 years ago

orkunkilinc commented 4 years ago

Hi all,

To avoid EMC/EMI problems and glitches on the SPI slave I want to reduce drive current of the GPIO on the STM32F103ZCT6.

I can confirm that reducing slew rate definitely fixes the problem but the functions to change it are not implemented on this core.

I basically want to change the correct register to reduce GPIO speed to 2MHZ with something like this. This is how it's done in STM32 Standart Peripheral Library.

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;

Thank You.

stevstrong commented 4 years ago

It is not clear how you set the output drive current on a SPI slave interface, because the slave only receives signals, and does not generate any.

For master SPI you can use the following function:

gpio_set_mode(GPIOx, bit_nr, (GPIO_CR_CNF_OUTPUT_PP | GPIO_CR_MODE_OUTPUT_2MHZ));

wherein

GPIOx = GPIOA for SPI1 and GPIOB for SPI2, and
bit_nr= the SPI SCK and MOSI pin bits for SPI1 (5/7) or SPI2 (13/15).

stevstrong commented 3 years ago

Closed due to lack of activity from OP.