LE910Cx mPCIe Hardware Design Guide
1VV0301510 Rev. 13 Page 32 of 73 2021-07-07
A flow chart showing the AT commands managing procedure is displayed below:
Figure 6: AT Commands Managing Procedure Flow Chart
Unconditional Restart
To unconditionally restart the LE910Cx-mPCIe, the pad PERST_N (pin 22) must be tied
low for at least 200 milliseconds and then released.
The hardware unconditional restart must not be used during normal device operation as
it does not detach the device from the network. It should be kept as an emergency exit
procedure to be performed in the rare event that the device gets stuck waiting for some
network or SIM responses.
Do not use any pull up resistor on the PERST_N line nor any totem pole digital output.
Using pull up resistors may bring to latch up problems on the LE910Cx-mPCIe.
The line PERST_N must be connected only in open collector configuration; the transistor
must be connected as close as possible to the PERST_N pin.
The unconditional hardware restart must always be implemented on the application
board as the software must be able to use it as an emergency exit procedure.
Delay = 300 msec
Disconnect PWR Supply
AT answer in
GO TO
“Modem ON Proc.”
“Start AT CMD”
END