BG770A-GL: Safe way to exit PSM prematurly?

IoT Modules LPWA Module
1

Hi all,

After entering PSM, I found the only way to exit PSM prematurly
and to get a network (+CREG=1 or 5) by disabling PSM with
AT+CPSMS=0 or AT+QPSMS=0 ?
But this command is stored in modem. Will it cause a Flash Wear Out if used to often?
Of is there another way to exit PSM prematurly ?

Thanks fro your help,
Jo

BG770A-GL sleep modes
2

Hi,I think you can set the value of T3412 to reduce PSM time

image
image566×137 21.2 KB

image
image841×579 83.5 KB

image
image821×124 13.6 KB

3

Hello @JoEmbedded

from the BG770A-GL&BG95xA-GL PSM Application Note document:

There are three scenarios to wake up the module:

- Forced: Hold the PON_TRIG high to wake up the module.

- Drive PWRKEY low to wake up the module. The UART port stays inaccessible until the
PON_TRIG is pulled high.

- Automatic: When the T3412 timer expires, the module wakes up automatically. The UART port stays inaccessible until the PON_TRIG is pulled high.

Thanks
Felix

4

Hello Mikey,

reducing the T3412 does not help, because the Network Providers have minimum limits, e.g. in Germany for “Telekom” it is 1hr, regardless of what you ask for. Often this much to long, e.g for Alarms…

Best regards, Jo

5

Hi Felix,
did you ever test any of these? “Wakeing up” the module from PSM only wakes it up, but still there is no network (creg replies 4).
The Problem ist a possible “Flash Wear Out” by often using forced registration.
Best regards, Jo

6

Hello @JoEmbedded

not with a BG770A-GL as I do not have this particular modem. I only read through the PSM documentation which also states that the modem should stay registered through a PSM phase so I am bit puzzled as to why this doesn’t work in your case.

Thanks
Felix