ST87M01 startup sequence

[Thierry Didi]

Hello

I am looking at the ST87M01 Startup sequence in ST87MXX Startup Application Note.

For configuring the ST87M01 (Band locks, eDRX, PSM ...), I understand that I need to "Stop the NBIOT Stack", enter my configuration with AT Commands, store this configuration in flash and restart the module.

• is this correct ?
• How do I "stop the NBIOT Stack" ?
• Is it possible to bypass this automatic startup, i.e. send a first "AT command" at startup, execute a specific set of configuration commands, trigger the network attachment ... without rebooting ?

Many thanks,

Thierry

[Didier HERROUIN]

Dear Thierry Didi,

The sequence is visible in the startup Application Note (slide 5).

You can stop the NBIOT stack by sending AT command : "AT+CFUN=0" (see on the right of the slide).

Then, if you modify the configuration, you must always send "AT#RESET=1" to save your parameters in the NVM (indeed, the reset is mandatory).

As reminder, for complete documentation, you must install the GUI (STSW-ST87MGUI :(at installation, it will create a folder containing numerous Application Notes). If you face difficulties to find this folder, you can access it via the "Help" menu in the GUI.

Best regards.

[Thierry Didi]

Hello Didier,

thanks for your reply - I have access to the documentation. I still have one question :

• When my CPU starts, I want to be sure that the ST87M01 configuration is the configuration that I need. But since the ST87M01 starts with whatever config is stored in its flash, I cannot be sure that this is what I need. This is the reason why I was planning to reconfigure the ST87M01 each time my CPU restarts:
• From your email, I see two solutions:
  • Reconfigure the ST87M01 each time my CPU starts, and reset the ST87M01 again with AT#RESET=1 if I understand your reply. It's a bit strange since this might lead to 2 ST87M01 resets at each startup, and also might cause to write in ST87M01 flash too often.
  • Send AT+CFUN=0, Read the actual config, and then AT+CFUN=1 if the config is the right one

Is one of these options the right one ? Or maybe there is another option ?

Many thanks

Thierry

[Didier HERROUIN · Accepted solution]

Dear Thierry Didi,

It depends on the number of powers up you have in mind, as the number of flash writing cycles is limited as you mentioned it.

Nevertheless, after a Power Sleep Mode or a "clean" power off (triggered with AT#poweroff" command), the parameters will be saved inside the ST87M01 NVM, so you have no reason to re-load them.

If you think about the first power-up, a network breakdown, or an exceptional case requesting recovery like the modem can not attach anymore to the network , reloading your configuration and applying a AT#RESET=1 is a good solution.

Best regards, 

[Thierry Didi]

Thanks Didier,

I was thinking of any startup which might happen during the whole life of the product (several years), and where we are not sure of the previous modem state.

anyway, I think that your reply is quite clear. The modem starts with whatever params are in its NVM, and a AT#RESET=1 or AT#POWEROFF is required if we want to modify them.

Best Regards

Thierry

[Didier HERROUIN]

Just a short correction about your last comment : you should send "AT+CFUN=0" to stop the stack, modify the configuration according to your needs, and finally send "AT#RESET=1" to save the configuration and reboot the module.

AT#PWROFF is the command to power off the module with a clean network detachment, saving NVM parameters.

[Thierry Didi]

ok thanks for the clarification,

best regards

Thierry