Power Profiling Kit RTT Documentation?

RE: Power Profiling Kit RTT Documentation?

CurtisHx — Fri, 10 Mar 2017 12:18:43 GMT

I got it from here: www.nordicsemi.com/.../33444

I fixed it by bumping up the wait after calling NRFJPROG_rtt_start to 1.5 seconds. I think the 1 second timeout was right on the hairy edge.

RE: Power Profiling Kit RTT Documentation?

wlgrd — Fri, 10 Mar 2017 08:30:36 GMT

And where did you get that dll from? It's all in the dll, so if it is the same as pynrfjprog 9.3.1 is using, I am out of ideas as to why this happens. Even so, if you catch that exception and just retries, will things continue to work or is the board reset?

RE: Power Profiling Kit RTT Documentation?

CurtisHx — Thu, 09 Mar 2017 14:21:48 GMT

This is all being written in C#, so I'm not using pynrfjprog library. I wrote a pinvoke wrapper around jlinkarm_nrf52_nrfjprog.dll and am using that to interact with the Jlink debugger.

RE: Power Profiling Kit RTT Documentation?

wlgrd — Thu, 09 Mar 2017 11:24:44 GMT

That I do now know. Have never seen this myself. Are you using pynrfjprog 9.3.1? This version fixed some minor issues regarding this write.

RE: Power Profiling Kit RTT Documentation?

CurtisHx — Wed, 08 Feb 2017 20:31:12 GMT

@wilhelmsen The write_stuffed method writes 0x00000001 to NRF_EGU0_BASE + TASKS_TRIGGER0_OFFSET. I'm occasionally getting a nrfjprog error along the lines of NVMC control is needed to write that position in my code. I've never seen it in the Python app. Do you know what causes the NVMC requirement to change on the PPK?

RE: Power Profiling Kit RTT Documentation?

wlgrd — Mon, 06 Feb 2017 11:40:43 GMT

SAMPLE_INTERVAL = 13.0e-6 self.sample_interval = SAMPLE_INTERVAL self.avg_interval = self.sample_interval * 10 thus sample interval for the trigger window is 13µs per sample, average window is 130µs, since it is an average of ten samples.

RE: Power Profiling Kit RTT Documentation?

CurtisHx — Wed, 01 Feb 2017 18:31:53 GMT

@wilhelmsen I think I have the reading values back working. Do you know what the time span each sample covers? I'm making the assumption that it's 15us because that's what [the documentation says], but I can't find anything definitive in the python code.

(infocenter.nordicsemi.com/.../PPK_user_guide_Intro.html

RE: Power Profiling Kit RTT Documentation?

wlgrd — Wed, 01 Feb 2017 12:10:29 GMT

That wait is critical for RTT operation in general. I don't know what has to settle, but yes, I have seen this as well.

RE: Power Profiling Kit RTT Documentation?

CurtisHx — Mon, 30 Jan 2017 15:27:30 GMT

Scratch all of my questions. It appears that 1 second wait after calling NRFJPROG_rtt_start is critical for proper PPK operation. I have no idea why.

RE: Power Profiling Kit RTT Documentation?

CurtisHx — Mon, 30 Jan 2017 15:23:13 GMT

I have a few questions:

Occasionally, the PPK will return all 0's when trying to read the Board ID, calibrations values, etc. My code goes through these steps :

a) Connect to the debugger at the max SWD speed. NRFJPROG_connect_to_emu_with_snr

b) Connect to the device. NRFJPROG_connect_to_device

c) Call system reset. NRFJPROG_sys_reset

d) Call go. 'NRFJPROG_go`

e) Start RTT. NRFJPROG_rtt_start

f) Wait for the RTT Control block to be found. Does a spin wait loop calling NRFJPROG_rtt_is_control_block_found until found is true. g) Read 200 characters over RTT. This will occasionally return all 0s.

The only difference I see between my startup code and the PPK Python code is the Python code calls time.sleep(1), where my code waits for the RTT control block. Should I just wait for 1 second instead of looking for the RTT control block?

RE: Power Profiling Kit RTT Documentation?

wlgrd — Mon, 12 Dec 2016 10:26:46 GMT

No, there are no RTT documentation for the PPK interface. It is quite easy to disect the python file, and look at (for instance) the RTT commands:

    RTT_CMD_TRIGGER_SET         = 0x01 
    RTT_CMD_AVG_NUM_SET         = 0x02 
    RTT_CMD_TRIG_WINDOW_SET     = 0x03 
    RTT_CMD_TRIG_INTERVAL_SET   = 0x04
    RTT_CMD_SINGLE_TRIG         = 0x05
    RTT_CMD_RUN                 = 0x06
    RTT_CMD_STOP                = 0x07
    RTT_CMD_RANGE_SET           = 0x08
    RTT_CMD_LCD_SET             = 0x09
    RTT_CMD_TRIG_STOP           = 0x0A
    RTT_CMD_CALIBRATE_OFFSET    = 0x0B
    RTT_CMD_DUT                 = 0x0C
    RTT_CMD_SETVDD              = 0x0D

and how to send them (rtt.py).

rtt.write([RTT_COMMANDS.RTT_CMD_RUN])


   def write(self, cmd):
        try:
            s = []
            s.append(STX)
            for byte in cmd:
                if byte == STX or byte == ETX or byte == ESC:
                    s.append(ESC)
                    s.append(byte ^ 0x20)
                else:
                    s.append(byte)
            s.append(ETX)
            try:
                self.nrfjprog.rtt_write(0, s, encoding=None)
                self.nrfjprog.write_u32(NRF_EGU0_BASE + TASKS_TRIGGER0_OFFSET, 0x00000001, 0)
                self.nrfjprog.go()
            except Exception as e:
                raise

Hopefully there will be an API coming soon. If there are any specifics you wonder about, please ask, and I will do my best to answer them.