RTT freeze after writing to UICR

RE: RTT freeze after writing to UICR

Gauthier — Wed, 20 Jun 2018 11:08:56 GMT

Note that it seems like the RTT is more stable with SDK 14.2 than with SDK 15.0.

RE: RTT freeze after writing to UICR

Jørgen Holmefjord — Wed, 20 Jun 2018 09:10:42 GMT

Yes, I will keep you updated on any findings/feedback and possible workarounds.

RE: RTT freeze after writing to UICR

Gauthier — Mon, 18 Jun 2018 08:23:00 GMT

Thanks, I trust you'll update this ticket with findings and possibly work arounds?

I saw that pynrfjprog 9.7 had _is_alive(), or something similar. Is there something I can do with that?

RE: RTT freeze after writing to UICR

Jørgen Holmefjord — Fri, 15 Jun 2018 14:58:06 GMT

Thank you for providing more details. We have been able to reproduce the issue internally. It seems there is some issue with the J-Link pack. We will investigate further, and/or report issue to Segger if this is a bug.

RE: RTT freeze after writing to UICR

Gauthier — Fri, 15 Jun 2018 07:49:56 GMT

It seems the issue wasn't with UICR, but had to do with timing between calls to pynrfjprog's rtt_write. Sorry about being misleading.

The original code failed when splitting a RTT command into several strings (sending max 15 chars at a time):

while command_string != '' and retries > 0:
    try:
        sent = self.api.rtt_write(0, bytes(command_string))
    except:
        BuiltIn().log_to_console("rtt_write error!")
    command_string = command_string[sent:]
    retries -= 1

if retries == 0:
    raise RpcError("Could not write command \""+command_string+"\"");

Adding a sleep after rtt_write helped:

while command_string != '' and retries > 0:
    try:
        sent = self.api.rtt_write(0, bytes(command_string))
        if sent == 0:               # Give time for a missed write to recover!
            time.sleep(0.1)
    except:
        BuiltIn().log_to_console("rtt_write error!")
    command_string = command_string[sent:]
    retries -= 1

if retries == 0:
    raise RpcError("Could not write command \""+command_string+"\"");

This seems to work for now, but I wonder about the implications.

The previous version tried to send 100 times in a row, I've tested 1000 as well, but the RTT never recovered. It seems that retrying too fast kept it in a state of inability.

pynrfjprog is 9.6.0.

nrfjprog 9.6.0

JLinkARM.dll version: 6.32c

Tagging helpful Jørgen Holmefjord

RE: RTT freeze after writing to UICR

Gauthier — Thu, 14 Jun 2018 14:00:21 GMT

JLinkExe version is V6.32c (was V6.10i, I just upgraded to match the version on a workstation where the issue doesn't show up (anymore)).

pynrfjprog is 9.6.0.

nrf-hil:/tmp$ nrfjprog -v
nrfjprog version: 9.4.0
JLinkARM.dll version: 6.32c

nrfjprog says 9.4.0 here, but we're dealing with pynrfjprog with venv.

Edit: upgraded nrfjprog to 9.6.0, we saw that pynrfjprog seemed to have a dependency to it. It did not help though.

Now my workstation and this test computer have the same versions of nrfjprog, pynrfjprog, and JLink. I don't know where to look further.

RE: RTT freeze after writing to UICR

Jørgen Holmefjord — Thu, 14 Jun 2018 13:21:29 GMT

Can you provide version numbers of nrfjprog and Segger-DLL?

RE: RTT freeze after writing to UICR

Gauthier — Tue, 12 Jun 2018 12:25:35 GMT

Thank you for that. Unfortunately it doesn't seem to make a difference.

RE: RTT freeze after writing to UICR

Jørgen Holmefjord — Fri, 08 Jun 2018 14:39:30 GMT

Can you test with debug_reset instead of sys_reset? We have seen some issues with re-init of rtt-buffers sometimes after sys_reset.

RE: RTT freeze after writing to UICR

Gauthier — Fri, 08 Jun 2018 13:14:16 GMT

[NRFJPROG DLL LOG]: FUNCTION: open_dll.
[NRFJPROG DLL LOG]: FUNCTION: open_dll.
[NRFJPROG DLL LOG]: FUNCTION: connect_to_emu_with_snr.
[NRFJPROG DLL LOG]: FUNCTION: connect_to_emu_with_snr.
[NRFJPROG DLL LOG]: FUNCTION: connect_to_emu_without_snr.
[NRFJPROG DLL LOG]: FUNCTION: enum_emu_snr.
[NRFJPROG DLL LOG]: Device "NRF52832_XXAA" selected.
[NRFJPROG DLL LOG]: FUNCTION: erase_uicr.
[NRFJPROG DLL LOG]: FUNCTION: erase_uicr.
[NRFJPROG DLL LOG]: Found SWD-DP with ID 0x2BA01477
[NRFJPROG DLL LOG]: AP-IDR: 0x24770011, Type: AHB-AP
[NRFJPROG DLL LOG]: Found Cortex-M4 r0p1, Little endian.
[NRFJPROG DLL LOG]: FPUnit: 6 code (BP) slots and 2 literal slots
[NRFJPROG DLL LOG]: CoreSight components:
[NRFJPROG DLL LOG]: ROMTbl 0 @ E00FF000
[NRFJPROG DLL LOG]: ROMTbl 0 [0]: FFF0F000, CID: B105E00D, PID: 000BB00C SCS
[NRFJPROG DLL LOG]: ROMTbl 0 [1]: FFF02000, CID: B105E00D, PID: 003BB002 DWT
[NRFJPROG DLL LOG]: ROMTbl 0 [2]: FFF03000, CID: B105E00D, PID: 002BB003 FPB
[NRFJPROG DLL LOG]: ROMTbl 0 [3]: FFF01000, CID: B105E00D, PID: 003BB001 ITM
[NRFJPROG DLL LOG]: ROMTbl 0 [4]: FFF41000, CID: B105900D, PID: 000BB9A1 TPIU
[NRFJPROG DLL LOG]: ROMTbl 0 [5]: FFF42000, CID: B105900D, PID: 000BB925 ETM
[NRFJPROG DLL LOG]: FUNCTION: sys_reset.
[NRFJPROG DLL LOG]: FUNCTION: sys_reset.
[NRFJPROG DLL LOG]: FUNCTION: go.
[NRFJPROG DLL LOG]: FUNCTION: go.
[NRFJPROG DLL LOG]: FUNCTION: rtt_start.
[NRFJPROG DLL LOG]: FUNCTION: rtt_start.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_read.
[NRFJPROG DLL LOG]: FUNCTION: rtt_stop.
[NRFJPROG DLL LOG]: FUNCTION: rtt_stop.
[NRFJPROG DLL LOG]: FUNCTION: sys_reset.
[NRFJPROG DLL LOG]: FUNCTION: sys_reset.
[NRFJPROG DLL LOG]: FUNCTION: go.
[NRFJPROG DLL LOG]: FUNCTION: go.
[NRFJPROG DLL LOG]: FUNCTION: rtt_start.
[NRFJPROG DLL LOG]: FUNCTION: rtt_start.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_is_control_block_found.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: rtt_write.
[NRFJPROG DLL LOG]: FUNCTION: disconnect_from_emu.
[NRFJPROG DLL LOG]: FUNCTION: disconnect_from_emu.
[NRFJPROG DLL LOG]: FUNCTION: close_dll.
[NRFJPROG DLL LOG]: FUNCTION: close_dll.

Right, this is what I got.

The reason why the writes and reads are duplicated is because the commands are sent 15 bytes at a time, and they are longer than that. I'm a bit surprised by the duplicated "go", "sys_reset", ...

Things go well until the second sys_reset, line 70/71.

rtt_start seems fine, the control block is found at least.

Subsequent rtt_write return 0 (number of bytes sent), until max number of retries (100) is reached.

To be honest, I'm not so sure this is related to UICR anymore.

RE: RTT freeze after writing to UICR

Jørgen Holmefjord — Fri, 08 Jun 2018 09:04:04 GMT

Can you try to enable logging by passing a filename to the parameter log_file_path? Remember to provide a separate filename to each instance of MultiAPI. Please upload the generated log files.

RE: RTT freeze after writing to UICR

Gauthier — Thu, 07 Jun 2018 11:56:53 GMT

It's `pynrfjprog` that isn't doing what I expect. I don't have the source, so I can't debug that.

`pynrfjprog`'s `rtt_write` does not manage to send all bytes to the devkit, if the devkit's UICR has just been flashed. I suspect that the devkit's write function is missing some kind of termination for the write itself?

RE: RTT freeze after writing to UICR

Jørgen Holmefjord — Mon, 28 May 2018 10:47:26 GMT

Have you tried debugging the device when you write the UICR registers, to see if any error codes are returned or if any hardfaults are happening?

RE: RTT freeze after writing to UICR

Gauthier — Wed, 23 May 2018 15:02:45 GMT

Thanks. I've tried running `nrfjprog --eraseall` and redo the test, behavior is unchanged.

I've been using pynrfjprog's `MultiAPI.write()` to write to address 0x10001080. Shouldn't pynrfjprog deal with read/modify/write?

RE: RTT freeze after writing to UICR

hmolesworth — Wed, 23 May 2018 14:19:47 GMT

Might I suggest looking at this post. UICR is not just a hardware register and some care is required when when writing, particularly multiple times.