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7 years, 4 months ago.
How to change pin (PA_1) purpose?
Hi guys, I have a problem which I've tried to solve myself, but I failed...
For one of my projects I'm using a Nucleo-F767ZI board and almost all GPIOs. Right now I'm having hard time with GPIO PA_1 which is originally connected to ethernet interface (datasheet page 77 -> RMII_REF_CLK).
So the problem is that when SB13 jumper is placed and PA_1 is connected to eth. interface I'm unable to use it for anything else! If I remove SB13 I can use it normally as any other pin, but how can I change software to use still unconnected GPIO as it would use PA_1 (I know that then I'll have to connect that pin to SB13 jumper with hard-wire, but that is not a problem...)? I found a lib with eth. GPIO configuration (https://developer.mbed.org/users/mbed_official/code/lwip-eth/file/9de8bd8ca1c8/arch/TARGET_STM/stm32f4_emac.c) - at least I think so...but how can I change it in my project?
HOW CAN I CHANGE ETHERNET GPIO CONFIGURATION?
Thank you all for your help & time.
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2 Answers
7 years, 4 months ago.
You have to remove SB13 in order to use it for something else. Otherwise the Ethernet chip on board will fight the signal and you can not expect it to work. It's well documented here http://www.st.com/content/ccc/resource/technical/document/user_manual/group0/26/49/90/2e/33/0d/4a/da/DM00244518/files/DM00244518.pdf/jcr:content/translations/en.DM00244518.pdf
Yes I understand that. I’ve already removed SB13 and I’m able to use PA_1 for something else but how can I configure another GPIO pin to work like PA_1 when connected to ethernet interface (I know I’d have to make a hard connection from that other GPIO to where PA_1 is originally connected - not a problem at all). My problem here is how to recofigure or change GPIOs that are used with ethernet interface...
posted by 20 Aug 2017Hello Ales,
For NUCLEO-F767ZI the GPIO pins used for the Ethernet interface (PA_1 included) are mapped as GPIO_AF11_ETH Ethernet Alternate function by calling the void HAL_ETH_MspInit(ETH_HandleTypeDef* heth) function which is implemented in the mbed-os/features/FEATURE_LWIP/lwip-interface/lwip-eth/arch/TARGET_STM/TARGET_STM32F7/TARGET_NUCLEO_F767ZI/stm32f7_eth_init.c file. So I'm afraid that to substitute PA_1 with other GPIO pin would be a quite complex task or maybe even impossible to achieve.
7 years, 4 months ago.
Hello Ales,
According to this datasheet, Table 12 - "STM32F765xx, STM32F767xx, STM32F768Ax and STM32F769xx alternate function mapping" only the PA1 pin can be mapped to the ETH_RMII_REF_CLK alternate function. Unfortunately it means that the STM32F767ZI microcontroller cannot use any other pin than PA1 to receive the 50MHz reference clock from the LAN8742A-CZ-TR PHY Ethernet chip.
Zoltan