Multiple Instances of SPI doesn't seem to be working.

[Rajat]

Hi Everyone

I am trying to use 2 instances of SPI SPI0 AND SPI2 for Epaper Display and MCP2515 CAN bus module respectively. 

Epaper and CAN are working fine if one of them is run. However if i run both of them , only one of the Peripherals work either CAN or the EPAPER.

What can be the possible reason for this behaviour.

I am suing SDK 15.0 with S140 Softdevice on Segger Embedded Studio on NRF52840.

Thanks 

Rajat!

[Rajat]

No, They are not overlapping with other peripherals.

This is what is happening now.

If i remove the Epaper from the hardware and test, it works fine.

But when i connect the epaper , CAN module doesn't get initalised.

[Kenneth]

Rajat said:

But when i connect the epaper , CAN module doesn't get initalised.

If you look at a logic analyzer plot between the two you can see what difference?

Maybe if you do a dump of the SPI configuration registers with and without the epaper you can identify the difference?

[Rajat]

 So far we are not using the Epaper, But still i would like to let you know that 

The problem was whenever i remove the Epaper, then CAN Works 

But whenever i connect the epaper , CAN initalization gets failed. 

I saw on logic analyzer which showed me that Epaper was causing the BUSY(MISO) pin to be low and hence instead of data that was supposed to be on MISO Lines , it became 0 .

So CAN  Initilazation failed.

Do You have any workaround for this in your mind?

Thanks!

[Kenneth]

How about using a 1kohm serie resistor in series with the MISO pin?

Best regards,
Kenneth

[scla]

Hi, I think I am running into this same issue. I know your post is several months old, but any chance you have this resolved? I noticed that when I compile the application with the optimizer set to "Debug" instead of "Optimize for size" (or levels 1-3), everything works fine. If I at all have gcc optimize, it looks like data sent to peripheral A is going to peripheral B.