Access to unit's IO pins through SWD interface.

[Leonid.K.]

Hello,

I need to get access to nRF51822 pins in order to test them and connected circuits.

I have access to SWD interface only.

By attempt to read ID register (A2=0, A3=0) the unit returns ACK(001) FAULT and following data: 0x85d88a3b.

By attempt to read CTRL/STAT register in the same frame (without additional INIT, IDLE cycles) the unit returns ACK(000).

What I'm doing wrong?

Is it possible to get an access to peripheral pins using SWD?

What should be a right SWD sequence  for this purpose?

Thanks in advance.

[awneil]

What are you using to connect to SWD ?

Leonid.K. said:

Is it possible to get an access to peripheral pins using SWD?

I don't think you can directly, but you can use it to access the registers which control the pins.

You could also use it to load & run test code (possibly to RAM) ...

[Leonid.K.]

I'm using IO pins of Lattice device controlled by JTAG Technologies Provision software by Python code.

[awneil]

So you're basically making your own debug adaptor?

That's going to be beyond the scope of the Nordic forum.

But, as far as the SWD interface goes, Nordic (like any other ARM licensee) has to abide by the standard spec - so look to the documentation from ARM...

You could also look at the open-source CMSIS-DAP.

But I would certainly start by using a standard debug probe - eg, JLink - and proving that you can achieve your requirements with that.

Then look at it's doing on the wires and, along with the ARM documentation, bas your implementation on that ...

[Leonid.K.]

OK. Thanks.

I also have Algocraft WN-8 programmer connected to SWD bus and burning it with customer's file.

I can try to get access to peripheral pins of the using it. But I don't really know which registers should be programmed.

[awneil]

Leonid.K. said:

I don't really know which registers should be programmed

See the Product Specification for register descriptions