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ramin_alimohammadi
ramin_alimohammadi
Associate II
June 26, 2015
Question

UNUSED PINS OF A PERIPHERAL

  • June 26, 2015
  • 2 replies
  • 751 views
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
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    2 replies

    Tesla DeLorean
    Tesla DeLorean
    Guru
    June 26, 2015
    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
    ramin_alimohammadiAuthor
    Associate II
    June 28, 2015
    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

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