Using RX/TX to output logging to to RN-42 Bluetooth

Development Boards Artemis
1

I have attached a RN-42 to the OLA board on the RX/TX pins and power it with the 3V3 pin. If I connect via the USB COM port, it successfully initiates a session (spits out the below and continues to spew data). I can then also connect through the bluetooth COM port and through that terminal can also view the data output, and initiate commands. So, the bluetooth connection is working in both directions. But, if I only connect over the bluetooth COM (without first connecting over USB), it never initiates the output. Is there a special port setting or something that I need to or something else I’m missing. I’ve been using mobaxterm but have also tried putty. Thanks!

SD init failed (second attempt). Is card present? Formatted?

Please ensure the SD card is formatted correctly using https://www.sdcard.org/downloads/formatter/

Config file read failed: SD offline

Artemis OpenLog v2.4

SD card offline

Datalogging offline

Serial logging offline

IMU online

Identifying Qwiic Muxes…

Identifying Qwiic Devices…

No Qwiic devices detected

Content-Type: text/csv

rtcDate,rtcTime,aX,aY,aZ,gX,gY,gZ,mX,mY,mZ,imu_degC,output_Hz,

01/01/2000,00:21:52.97,753.42,-191.41,-606.93,-1.56,-0.02,-0.79,-68.25,77.40,48.75,28.56,0.0,

01/01/2000,00:21:53.07,753.42,-196.78,-601.07,-0.95,0.11,-1.27,-69.45,78.15,48.30,28.70,20.0,

01/01/2000,00:21:53.17,760.74,-199.71,-602.05,-0.79,-0.05,-0.17,-70.20,78.15,49.50,28.56,15.0,

01/01/2000,00:21:53.27,761.23,-183.11,-622.07,-0.03,1.07,-1.85,-68.85,77.55,47.70,28.60,13.333,

2

How is it being powered? Pg 8 mentions https://www.sparkfun.com/datasheets/Wir … -42-ds.pdf that if you have a slow power ramp-up things might get wonky; can you probe the chip’s pins by chance to view activity on relevant pins from pg 4?

Does it do the same thing (same debug printout) with an SD card in the OLA?

3

I am powering the Artemis board with USB-C and have the RN-42 connected to the 3v3 pin.

The SD card behavior is fidgety too. Sometimes with no SD card, it only gets to line 3 of the debug print out and just hangs there. Other times it spits out as I had pasted before, where it streams data. I would assume it would proceed with or without an SD card, and I believe I read that is the expected behavior.

With the SD card in, sometimes it works, sometimes it doesn’t. Often it induces a few characters of garbage on the terminal output.

As of now, I can’t get it to output anything other than the first 3 lines (up to ‘Config file read failed: SD offline’), when the SD card is out. With the SD card in, nothing happens. I have tried two different SD card brands/sizes, and reloaded the firware (OpenLog_Artemis-V10-v24.bin).

4

Hi,

I’m wondering if this could be a power “brown-out” issue?

Please see this discussion for more details and possible solutions (special firmware and adding an extra capacitor):

viewtopic.php?p=236898#p236898

Best wishes,

Paul

5

I tried that firmware but no changes. I did upload bootloader, and that seems to factory reset the whole thing, whereas uploading new firmware does not. The bluetooth now seems to work without having to connect over USB first. One thing I’ve found out is that connecting over USB forces a reboot which may be a clue to what setting I accidentally changed. Anyways, I’m working for now, and now know how to reset the board to a known state (well, I think I do).

6

OK, so I just noticed that if I power via USB (this is the only power source I’ve used so far), it doesn’t seem to boot. To be more specific, when I plug it in to USB (but don’t connect serial), there is no led action (actually a very quick yellow light, but otherwise everything dead), whereas if I hit reset, I get a held blue, and then standard processor/tx/pwr blinkies. I noticed connecting over COM forces a boot. So I guess my problem was that I was not getting to booting by just powering it. Is there a setting to force booting (or maybe it’s forcing waking or initiating tx out). Thanks for all the replies!

7

I’m glad it’s ~working!

Please try the extra capacitor- if you have one available. It may help, especially with the extra power draw of the BT module.

Best wishes,

Paul

8

I got a battery and adapted to the power connector and the behavior now is to consistently go through the ‘boot’ sequence; and I can consistently get bluetooth from there. Powering from battery is my end goal, so I’ll call it good. With USB power, I just need to remember to hit reset to get it running.