Using peripherals when they share (some of) the same pins

[nicholas2399]

Posted on July 25, 2012 at 10:47

I am using the STM32F103C8T6. I notice that some of the peripherals share the same pins. What I am wondering is whether it is possible to use these peripherals in these circumstances.

The specific case I am looking at are UART3 and SPI2, neither of which can be re-mapped (not on the version of the device I am using) Now UART3 is on pins PB10, PB11, PB12, PB13 and PB14 (I am only interested in TX and RX on PB10 and PB11), whereas SPI2 is on pins PB12, PB13, PB14, PB15 ( I am only interested in SCK, MISO and MOSI on PB13, PB14, PB15)  Is it possible to use both peripherals in this way? If so what mechanism stops the UART CTS and RTS functions affecting the SPI2 SCK and MISO functions? Thanks in advance Nick #peripherals-stm32f103c8t6

[Tesla DeLorean]

Posted on July 26, 2012 at 21:03

Good grief! This thread has run off the rails.

Question : Can I use a two pin  USART3 (PB10, PB11) with a three pin SPI2 (PB13, PB14, PB15)  on a STM32F103C8T6. Answer : Yes you should be able to do that, don't enable flow control or synchronous clocking on the USART, and CTS, RTS, CK won't clash with other pins. No remapping required.

[Andrew Neil]

Posted on July 27, 2012 at 00:35

''Maybe you could be more specific which peripherals exactly you'd like to use''

How much more specific does it need to be:

''Now UART3 is on pins PB10, PB11, PB12, PB13 and PB14 (I am only interested in TX and RX on PB10 and PB11), whereas SPI2 is on pins PB12, PB13, PB14, PB15 ( I am only interested in SCK, MISO and MOSI on PB13, PB14, PB15)''