[bug] SPI Transfer not updating buffer values

[MattStep90]

Hardware

Arduino Nano Matter V0.3

Core version

2.2.0

Arduino IDE version

2.3.2

Operating system

Windows 10

Radio stack variant

Matter

OpenThread Border Router device (if using Matter)

No response

Issue description

The SPI.transfer(buffer, size) function does not update the buffer with values returned from the SPI bus as is expected in the standardized Arduino SPI library. This breaks compatibility with many other libraries where the SPI.transfer function is used and expects that the buffer provided will be updated with return values.

Serial output

No response

RTT output (if using Matter)

No response

Minimal reproducer code

No response

[silabs-bozont]

Hello @MattStep90,
Thank you for the bug report! According to the docs you're right - SPI.transfer(buffer, size) should update the original buffer with the received values. I'm working on a fix and it'll be included in the next release!
In the meantime you can use this function to send and receive multiple bytes in a single call. It works similarly, the only difference is that you also have to provide a separate receive buffer.