We have a SL6087 with firmware R7.46 without any OpenAT application running.
In this particular application we set AT+W32K=1 and control the sleep mode with DTR signal.
To reduce communication we monitor the module by looking at the FLASH_LED signal.
Occasionally the module seems to “hang” somehow, and it’s not possible to power off normally (with the AT+CPOF sequence) as the module no longer responds to any AT commands.
When that happens, it’s also not possible to even RESET the module using the documented reset procedure.
The only thing that seems to help is to remove power completely, or reduce power below usable levels.
This hang can happen after hours, or after several days of operation, making it very difficult to test things.
Power draw from the module when it enters this hang is a solid 84mA @ 3.8V.
I haven’t seen anything in documentation that the emergency reset is inoperable when something happens to the module in W32K mode.
Has anyone else run into this problem? Does anyone know if upgrading the module firmware helps?