UNUSED PINS OF A PERIPHERAL

ramin_alimohammadi · ‎2015-06-26

Posted on June 27, 2015 at 00:51

Hi,

when I use a peripheral with some unused pins, can I use other alternate functions of those pins (for other peripherals)?

for example, in STM32f407, I use SPI2 with unused SPI2_NSS (pin 140). can I use this pin as I2C1_SDA (SPI2_NSS and I2C1_SDA are both defined as alternate functions for pin 140 in datasheet)?

thanks

Tesla DeLorean · ‎2015-06-26

Posted on June 27, 2015 at 01:31

Each pin can select a single peripheral function from the list defined in the Data Manual. Only use TIM1_CH4, you don't need to route any of the channels to pins.

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ramin_alimohammadi · ‎2015-06-28

Posted on June 28, 2015 at 12:07

thanks for your reply,

You mean that I can assign a pin to any defined alternate function(just one)? in my above example, I want to use both SPI2 and I2C1. pin 140 (of STM32F407-ZGT6 LQFP 144-PIN) contains I2C1_SDA and SPI2_NSS. but my SPI2 application don't need to NSS, can I assign I2C1_SDA to this pin (pin 140, port PB9)? does using I2C1 conflict with SPI2 by using pin 140?

thanks