Telit CFUN, curr. consump. & Storing variables in AlarmMode

Wireless & IoT
1

I’m using the GM862-GPS.

According to the spec. CFUN=4 shuts down GSM connection.

CFUN=0 keeps GSM running.

how come the CFUN=4 consumes 18 mA and CFUN=0 goes down to 3.3-9mA (this is according to spec. and my trials).

What is consuming so much power in CFUN=4 ?

What is the point in using CFUN=4.

I’m trying to get the minimal current consumption, but it seems hard to get lower than 5-10mA.

I know i can set the Alarm timer and shut the module down completely, but then my program starts all over again when the alarm goes of.

Would it be possible to save some data somewhere in the memory and read this upon start up from Alarm-mode ?

I was thinking about “mis-using” the phonebook or “draft sms” to store a reference position before goes to Alarm-mode. Is there a smarter way ?

2

?? on power consumption, but you can write a file to the Telit’s internal memory (advised against by Telit due to limited # of write/deletes). I have done this and stored sensor readings just to see if I could. I am wanting to keep a running average of a sensor and would like to save to external memory without adding my Arduino back on. Its rumored that there is an SD card library (using SPI I take it). This is mentioned on Telet’s forum, Roundsolutions.com and on the Sparkfun forum. Sparkfun tech support is trying to get me info on this but no luck yet. If I hear more I’ll let you know.

3

f1fan3584:
?? on power consumption, but you can write a file to the Telit’s internal memory (advised against by Telit due to limited # of write/deletes). I have done this and stored sensor readings just to see if I could. I am wanting to keep a running average of a sensor and would like to save to external memory without adding my Arduino back on. Its rumored that there is an SD card library (using SPI I take it). This is mentioned on Telet’s forum, Roundsolutions.com and on the Sparkfun forum. Sparkfun tech support is trying to get me info on this but no luck yet. If I hear more I’ll let you know.

That sound quite cool. I actually do have a SD card logger for my arduino but it would be nice to do it directly from the Telit.

I have also read about the recommendation not to use the telit as a datalogger.

Do you know how many read/write/delete cycle it will take ?

4

Telit forum lists # of cycles as 100000. I got the python sd card library from Sparkfun today, so I’m looking forward to trying it.

5

f1fan3584:
Telit forum lists # of cycles as 100000. I got the python sd card library from Sparkfun today, so I’m looking forward to trying it.

well 100.000 is not a lot if it’s used as a datalogger. However i only need to store one position every time i activate the tracker. So after all it might be ok for me…

Still the SD card lib would be nice to try.

6

How do I get my hands on that SD card lib?

7

Call or email Sparkfun’s tech support, I believe John at Sparkfun’s helped me. Also, I recommend getting on Telit’s forum, there has been some discussion of this as well with some users implementing it. I have the Python library now, but not time to work on it.