I2C initialization on registers level

[Leonid.K.]

Hello,

I work with the ATE using Algocraft WN series programmer.

It has directly access to GPIO registers through SWD interface with WRITE / READ / COMPARE commands.

I already succeed to toggle and read states on GPIO pins.

Now I need to initialize I2C interface and work with external I2C peripheral devices.

How to initialize the I2C interface correctly?

Is there any description of the proper registers write/read sequence?

Thanks in advance.

[Nguyen Hoan Hoang]

you can download the data sheet from https://infocenter.nordicsemi.com/index.jsp.  It contains all the information you need.

[Jørgen Holmefjord]

Hi,

0xBFFFFFFF and 0xFFFFFF7F is not valid values in the PSELSDA/PSELSCL registers. These registers should be set to the GPIO pin number (0x7 and 0x1E in your case), of 0xFFFFFFFF in case the pin is Disconnected:

The address register should also be set before starting the transfer.

I verified that these commands works with nrfjprog:

nrfjprog --memwr 0x40003500 --val 0x00000000
nrfjprog --memwr 0x50000778 --val 0x00000302
nrfjprog --memwr 0x5000071c --val 0x0000060C
nrfjprog --memwr 0x40000528 --val 0x00000009
nrfjprog --memwr 0x4000350c --val 0x1E
nrfjprog --memwr 0x40003508 --val 0x7
nrfjprog --memwr 0x40003524 --val 0x01980000
nrfjprog --memwr 0x40003500 --val 0x00000005
nrfjprog --memwr 0x40003588 --val 0x00000055
nrfjprog --memwr 0x40003008 --val 0x00000001

This generates the following output on the pins:

Best regards,
Jørgen

[Leonid.K.]

Dear Jorgen,

Thanks a lot for your answer.

But it still doesn't work for me.

I did exactly what you mentioned:

But still don't see any activity on SDA, SCL lines.

May be something else need?

Best regards.

Leonid.

[Leonid.K.]

The SCL line goes HIGH, and SDA line remains LOW. 

If I run code specially written for I2C, I see correct lines activities.

[Leonid.K.]

So, on pic 1 shown how it should be,

and here what I have by a first running after working code:

Please pay attention to low SCK level (why?) and NACK with the same slave address.

The repeated run causes to falling LOW the SDA line.

[Jørgen Holmefjord]

Did you verify that the PSEL registers got set correctly? I'm not sure about how your masks work, but my point was that you need to set the registers to 0x0000001E and 0x00000007 to get correct behavior.

[Leonid.K.]

Looks like you right.

It should be 

It works now.

Thanks a lot.