cpu: mips_pic32_common: Implement GPIO IRQ

[francois-berder]

Contribution description

This PR implements periph_gpio_irq for PIC32 devices. It also updates the SAUL configuration on the pic32-clicker and pic32-wifire.
Note that the implementation differs slightly between PIC32MX and PIC32MZ. While implementing this feature, it appeared that the PIC32MX is only able to trigger interrupts on any edge. This means that it will probably be less reliable than on the PIC32MZ.

Testing procedure

Build and flash test/buttons on a pic32-clicker or pic32-wifire. On a pic32-wifire, pushing a button pulls the line to 3V3, while on pic32-clicker, pushing a button pulls down the line.

Issues/PRs references

None

[MrKevinWeiss]

I tested on the pic32-wifire and everything works as expected with both the tests/buttons and examples/default with SAUL.

I also tried on the pic32-clicker but seemed to have some problems with the terminal, it appears that BOARD=pic32-clicker make term doesn't return anything (even an error) so I added a USB to UART converter and connected it to the RX and TX pins before finding out that they are not the correct pins... I don't know why the RF5 and RF4 were chosen as on the board they indicate I2C lines.

I digress, I attached the lines to the RF4/5 and tried to get some terminal output... Still nothing so I tried just the tests/leds... nothing.

I also noticed that the LEDs on the board say LD1(RD4) and LD2(RD1) and in the board.h the LEDs were set to PB1 and PB2. So I tried to change it and reflashed the tests/leds with what should be fixed LED porting.

It seems like you have the pic32-clicker working, does the tests/leds actually work?
How do you flash the pic32-clicker?
I use BOARD=pic32-clicker BUILD_IN_DOCKER=1 make flash -C tests/leds with the pickit3 updated as per the documentation in dist/tools/pic32prog/doc.md

[francois-berder]

I think you simply do not have the right board. Given your comments, it seems that you have a PIC32MX clicker while pic32-clicker actually refers to the 6LoWPAN clicker. Yes, it is confusing and we should definitely rename the board.

I also tried on the pic32-clicker but seemed to have some problems with the terminal, it appears that BOARD=pic32-clicker make term doesn't return anything (even an error)

Both boards do not share the same CPU so I am not surprised that you see nothing in the terminal. I assume other changes in the code are needed.

It seems like you have the pic32-clicker working, does the tests/leds actually work?

I do not think I tried this test before but I was able to turn on LEDs using SAUL when the clicker was programmed with examples/default

How do you flash the pic32-clicker?

I use a pickit 2 with pic32prog, it is slow but it works. Unfortunately, it seems that the pinout of the connector on the left side of the board does not match the standard Microchip ISCP on the PIC32MX clicker.

[benpicco]

Looks good to me - maybe @MrKevinWeiss can give it another test?

[MrKevinWeiss]

I think you simply do not have the right board. Given your comments, it seems that you have a PIC32MX clicker while pic32-clicker actually refers to the 6LoWPAN clicker. Yes, it is confusing and we should definitely rename the board.

Doh! That explains it 😄

Looks good to me - maybe @MrKevinWeiss can give it another test?

Will do, just need to get to the hardware, should be by the end of the day.

[MrKevinWeiss]

Retested on the wifire and it works. As I don't have the clicker this is the best we can get!

[benpicco]

I think that's good enough :)