X-NUCLEO-BNRG2A1: how to set EXTI on PB14 instead of PA0?

[paul19]

Table 4 of UM2667 says:

PA0_SPI_IRQ_PB14_BNRG1BOOT:

Default STM32 port = PA0

Optional STM32 port = PB14

To use the optional port, mount R82 and unmount R85

However, on my X-NUCLEO-BNRG2A1, both R82 and R85 are mounted. What should I do?

[paul19]

Ok, I got it working despite what I think are errors in UM2667.

"Default STM32 port = PA0, Optional STM32 port = PB14" => wrong. By default, the X-NUCLEO-BNRG2A1 uses *both* PA0 and PB14.

"To use the optional port, mount R82 and unmount R85" => wrong, there is no need to mount or unmount anything. If you want to use PB14, all you need to do is:

1. to physically connect PB14 of the X-NUCLEO-BNRG2A1 to PB14 of the Nucleo-64, and
2. to change the code from STM32CubeMX so that it uses PB14 instead of PA0. This requires:
   1. to assign pin PB14 to GPIO_EXTI14,
   2. in NVIC, to Enable interrupts for "EXTI Line[15:10]",
   3. in BLE Software Pack, to set "Exti Line" to PB14.

Now if you want to use PA0 for another purpose (for example plugging another shield that uses PA0), there's one more step. Indeed, if the other shield send signal on PA0, it will prevent the X-NUCLEO-BNRG2A1 from working. So you need to tell the X-NUCLEO-BNRG2A1 that it shall not listen to PA0. This is done by unsoldering R85.

Maybe another error in the doc: page 12, CN10 morpho connector, "Pass-Through: Female on Bottom and Male on Top". Well, because the X-NUCLEO-BNRG2A1 actually uses PB14, I don't believe you can call this pin "Pass-Through".

[Imen.D]

Hello @paul19​ and thanks for your reported errors.

I escalated your feedback internally to to involved team for check and take necessary action for correction.

Thanks

Imen

[Imen.D · Accepted solution]

Hi @paul19​ ,

Our team is working to correct the reported errors in the UM2667.

The update will be visible online in few days.

So, keep an eye out for the coming update.

Thanks

Imen