NRF52-DK embedded serial port issues on Ubuntu

[tomasz.szewczyk]

Hi!

I have some troubles with making embedded serial port working on NRF52-DK. Basically I can receive data sent by nrf chip but I cant write. When I write something using any terminal nothing happens on the board.

HOWEVER this is not always true, sometimes it just works. I had connected multiple boards and sometimes they works. I cant find out when it works and when it doesn't.

I'm using following NRF52-DKs:

PCA10040
1.2.1
2017.44

JLink version:

$ JLinkExe
SEGGER J-Link Commander V6.22d (Compiled Dec 14 2017 18:34:26)
DLL version V6.22d, compiled Dec 14 2017 18:34:21

OS:

Linux thinkpad 4.14.11-041411-generic #201801022143 SMP Tue Jan 2 21:44:21 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Dmesg while disconnecting and connecting two boards:

[ 3280.560236] usb 1-4.1.4: USB disconnect, device number 18
[ 3280.611266] FAT-fs (sda): unable to read boot sector to mark fs as dirty
[ 3281.328193] usb 1-4.1.1: USB disconnect, device number 19
[ 3281.371319] FAT-fs (sdb): unable to read boot sector to mark fs as dirty
[ 3283.839446] usb 1-4.1.1: new high-speed USB device number 20 using xhci_hcd
[ 3283.939989] usb 1-4.1.1: config 1 interface 1 altsetting 0 bulk endpoint 0x83 has invalid maxpacket 64
[ 3283.939994] usb 1-4.1.1: config 1 interface 1 altsetting 0 bulk endpoint 0x4 has invalid maxpacket 64
[ 3283.940436] usb 1-4.1.1: New USB device found, idVendor=1366, idProduct=1015
[ 3283.940440] usb 1-4.1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3283.940443] usb 1-4.1.1: Product: J-Link
[ 3283.940445] usb 1-4.1.1: Manufacturer: SEGGER
[ 3283.940448] usb 1-4.1.1: SerialNumber: 000682278658
[ 3289.143874] cdc_acm 1-4.1.1:1.0: ttyACM0: USB ACM device
[ 3289.144501] usb-storage 1-4.1.1:1.3: USB Mass Storage device detected
[ 3289.144588] scsi host0: usb-storage 1-4.1.1:1.3
[ 3289.367369] usb 1-4.1.4: new high-speed USB device number 21 using xhci_hcd
[ 3289.471937] usb 1-4.1.4: config 1 interface 1 altsetting 0 bulk endpoint 0x83 has invalid maxpacket 64
[ 3289.471942] usb 1-4.1.4: config 1 interface 1 altsetting 0 bulk endpoint 0x4 has invalid maxpacket 64
[ 3289.472431] usb 1-4.1.4: New USB device found, idVendor=1366, idProduct=1015
[ 3289.472435] usb 1-4.1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3289.472437] usb 1-4.1.4: Product: J-Link
[ 3289.472440] usb 1-4.1.4: Manufacturer: SEGGER
[ 3289.472443] usb 1-4.1.4: SerialNumber: 000682577482
[ 3289.474096] cdc_acm 1-4.1.4:1.0: ttyACM1: USB ACM device
[ 3289.475022] usb-storage 1-4.1.4:1.3: USB Mass Storage device detected
[ 3289.477943] scsi host1: usb-storage 1-4.1.4:1.3
[ 3290.167746] scsi 0:0:0:0: Direct-Access     SEGGER   MSD Volume       1.00 PQ: 0 ANSI: 4
[ 3290.168195] sd 0:0:0:0: Attached scsi generic sg0 type 0
[ 3290.168569] sd 0:0:0:0: [sda] 21829 512-byte logical blocks: (11.2 MB/10.7 MiB)
[ 3290.168787] sd 0:0:0:0: [sda] Write Protect is off
[ 3290.168789] sd 0:0:0:0: [sda] Mode Sense: 0b 00 00 08
[ 3290.168999] sd 0:0:0:0: [sda] No Caching mode page found
[ 3290.169003] sd 0:0:0:0: [sda] Assuming drive cache: write through
[ 3290.172313]  sda:
[ 3290.173447] sd 0:0:0:0: [sda] Attached SCSI removable disk
[ 3290.487660] scsi 1:0:0:0: Direct-Access     SEGGER   MSD Volume       1.00 PQ: 0 ANSI: 4
[ 3290.487955] sd 1:0:0:0: Attached scsi generic sg1 type 0
[ 3290.488242] sd 1:0:0:0: [sdb] 21829 512-byte logical blocks: (11.2 MB/10.7 MiB)
[ 3290.488460] sd 1:0:0:0: [sdb] Write Protect is off
[ 3290.488461] sd 1:0:0:0: [sdb] Mode Sense: 0b 00 00 08
[ 3290.488673] sd 1:0:0:0: [sdb] No Caching mode page found
[ 3290.488676] sd 1:0:0:0: [sdb] Assuming drive cache: write through
[ 3290.491873]  sdb:
[ 3290.492697] sd 1:0:0:0: [sdb] Attached SCSI removable disk

When I was recording this log 682577482 was working. The other one didn's and both weren't working a moment before...

What can I do about it? Where to look for the reason of this strange behavior?

Thanks, Tomek

[Matt]

Are you talking about Linux_pc_1 <--uart--> PCA10040 <-- BLE --> PCA10040 <-- uart --> Linux_pc_2 ?

[tomasz.szewczyk]

I'm taking about Linux_pc_1 <--usb--> PCA10040 <--uart--> nRF52 and I have two identical independent setups

[Matt]

Have you tried with a Windows 7 pc? How could you get the JLink dll to work in Linux by the way?

[Stian Røed Hafskjold]

Hi, I'm sorry but I'm unable to reproduce the issue. We've had some issues with the Segger FW earlier where the CTS remainded inactive (high) after flashing and resetting the board. Could you try to manually pull the CTS line to GND to see if that helps? Have you tried with both flow control enabled and disabled? Any difference?

[ivansanchez]

Try disabling ModemManager temporarily. There is a known issue where ModemManager sends AT commands to any TTY devices, and if your firmware receives an AT command by mistake, it might misbehave or enter a buggy state. Note that output from ModemManager does not appear in dmesg, but in /var/log/syslog if my memory serves right.

This has been patched upstream (but will still require some firmware updates in the segger interface MCU so it can provide proper USB descriptors - right now they advertise support for AT commands).