SPI transfer problem between SAM D21 and STM32 on MKRWAN1310

[tohlh]

I've managed to use SPI to transmit a byte from SAM D21 as master to STM32 as slave but not the other way around. The example codes I tested with HAL_SPI_TransmitReceive, HAL_SPI_TransmitReceive_IT and HAL_SPI_TransmitReceive_DMA on STM32 can be seen from https://github.com/tohlh/MKRWAN1310-SPI-Test. Appreciate if anyone can offer some help.

[tohlh]

I also tested the device in the following GPIO modes on PB14 (MISO) pin:

1. GPIO_InitStruct.Mode = GPIO_MODE_AF_PP; GPIO_InitStruct.Pull = GPIO_NOPULL
2. GPIO_InitStruct.Mode = GPIO_MODE_AF_OD; GPIO_InitStruct.Pull = GPIO_PULLUP

...but none of them is working.

[tohlh]

Could it be possible that PA15 on SAM D21 is not connected to PB14 on STM32?

I was trying to detect the interrupt on PB14 if it's raised to HIGH on SAM D21, but nothing was detected.