[neilh20]

No problem – I appreciate the earlier tip.
What I haven’t figure out is there another manual that specifies +CREG cmd – it isn’t in the user manual I’m using.
I have seen it before where latest manual “inherits” a context of another set of cmds specified in an common manual.

[neilh20]

Thanks for the tips here.
I’ve also had trouble with a new Hologram SIM registering to the cell network with a Digi XB3M1.
I had a working hologram SIM that connected straight away, and then would power off and swop in the new Hologram enabled SIM, and it would poll the cell tower and not work.
I started trying about 2weeks ago, had to move on to a few other items, came back to it.
Tried a few more times yesterday, added the tip above, and it worked, and ran overnight OK.
I’m based 0.23.15 (but latest github.com/EnviroDIY/TinyGSM) and using DigiXBeeCellularTransparent.cpp
I included and monitored the AT responses
bool DigiXBeeCellularTransparent::extraModemSetup(void)
added at the end
gsmModem.sendAT(GF(“+CREG”));
and it sent back an ERROR
but then the XB3M1 registered.
Seems like its a magic recipe workaround of some sort, but no idea if this really works till I try registering my next sim.

The code is here – search “+CREG”
The first commented out “+CREG” is how I had it.
Then I introduced an algorithm to only issue “+CREG” it if has been monitoring for 100 times for the next time I register a sim.
https://github.com/neilh10/ModularSensors/blob/rel1_dvlp1m/src/modems/DigiXBeeCellularTransparent.cpp

The output is

Version 11413 <–DigiXBeeCellularTransparent
Loop=Sec] rx db : Status ‘ Operator ‘ #Polled Cell Status every 1sec
0=5.28] 0:0x22 ‘OK’
1=6.30] 0:0x22 ‘OK’
2=7.32] 0:0x22 ‘OK’
3=8.34] 0:0x22 ‘OK’
4=9.35] 0:0xff ‘OK’
5=10.37] 0:0xff ‘OK’
6=11.39] 0:0xff ‘OK’
7=12.41] 0:0xff ‘OK’
8=13.43] 0:0xff ‘OK’
9=14.44] 0:0x22 ‘OK’
10=15.46] 0:0x22 ‘OK’
11=16.48] 0:0x22 ‘OK’
12=17.50] 0:0x22 ‘OK’
13=18.52] 0:0x22 ‘OK’
14=19.53] 0:0x22 ‘OK’
15=20.55] 0:0x22 ‘OK’
16=21.57] 0:0x23 ‘OK’ Cnt=1
17=22.59] 0:0x0 ‘AT&T Hologram’ Cnt=2
Cell scan ‘ S MCC:310 MNC:410 Area:35651 CID:169103376 Signal:-98 ‘
… Setup successful! <–DigiXBeeCellularTransparent

[neilh20]

Thanks.
The cct V0.5b shows an option of connecting the Xbee to the LiIon V_bat – which can get to 4.2V – and a very nice low impedance for the Cellular Tx power requirements.
So if the Xbee-V1-UT/XB3-C-A2 Cellular @ 4.2V was pulling up, that would over drive the mega1284 pins above their Vcc (3.3V).
At some point the megas1284 protection diodes start to conduct. The issue not stated in the Xbee docs is if there is a -RESET pullup. If there is no pull-up, or its week (greater than 100K) its probably workable.

[neilh20]

Oh good to hear it works.
What pin are you using on the Mayfly.? I could see the references in the code on modemConnect() but couldn’t find any designation.

One of the problems is that the ATmega1284 doesn’t have any 5V compatible pins, so it may cause some unpredictable behaviour if it pulls the mega1284 pin up too hard – which depends on the Xbee.

One way would be to decouple with a NMOSFET with low drive voltage – eg with legs/TO92-3 TN0702N3-G – it turns on between 0.5-1V
https://www.digikey.com/products/en?keywords=TN0702N3

http://ww1.microchip.com/downloads/en/DeviceDoc/TN0702%20C080813.pdf
It doesn’t need an R on the Gate where it interfaces to the micro, and probably doesn’t needs a pullup on the Drain, as there may be enough pull up in the Xbee – otherwise I would recommend a 10K-1M R. Its only activated for short period of time so the R doesn’t really matter – except it must be low enough to guarentee that the MOSFET turns OFF.

How To Use MOSFET – Beginner’s Tutorial

[neilh20]

I’ve also had this problem with the Xbee S6 WiFi. However I’ve lowered the polling rate and a few other tweaks of the TinyGSM and its been better https://github.com/neilh10/TinyGSM.
@cal the Mayfly 0.5b schematic diagram of the U6/XBEE-1XBEE-1_LOCK shows the RESET pin5 – the schematic symbol of circle on the mainbody is typically a way of indicating the RESET is pulled low to activate it, also sometimes indicated as -RESET.

I’d be interested in the solution for where to connect the Xbee reset line to the Mega1284 – but haven’t tried any options yet.

[neilh20]

Nice write up on github thankyou. I’ve got the ParticleIO WiFi going for one project. Particularly interesting your TDS references thanks.

[neilh20]

hi @frbiggs I’ve used the teensy – but it comes in a number of flavors.
Checkout https://github.com/duff2013/SDI12_T3
IHMO the Teensy3.5 also has +5V tolerant pins.
The Teensy3.5 and 3.6 processors have some nice ram. https://blog.adafruit.com/2016/10/06/new-products-teensy-3-5-teensy-3-6/

Can you say what your context is – are you looking to use ModularSensors which also has a lot of infrastructure support.

[neilh20]

Thanks for all the help in diving into the ModularSensors code.
I’ve captured my notes on how to work as a developer with the layers of ModularSensors/TinGSM/KellerLib/Arduino code – https://github.com/neilh10/ModularSensors/wiki/git-cmds-for-preparing-for-a-PR This is really my cheat sheet – but available if anybody else wants it.

[neilh20]

I’ve put a discussion of measuring LiIon voltage https://github.com/EnviroDIY/ModularSensors/issues/196
I’m seeing a divergence in between two different sources of measuring LiIon from V_Batt and ExtVolt/ADS1115.

[neilh20]

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