User's Manual

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Note d’étude / Technical document : URD1 – 5625.1 – 006 / 69796 Edition 03
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Figure 24
USB Connection between MO300 and host
To use USB link between Host and MO300, specific SAGEM USB drivers are needed and available on SAGEM
www site and on request.
As soon as USB link is detected by the MO300 module, the AT command responses are sent on USB link and
RS232 - UART1 interface is de-activated.
RS232 - UART2 interface for traces is still operational.
USB and RS232 - UART1 are then exclusive and priority is given to the USB interface.
CMD I/O command can be used if required, see "Stopping the module" chapter.
3.8 Backup battery
3.8.1 Backup battery function feature
A backup battery can be connected to the module in the aim to supply internal RTC (Real Time Clock) when the
main battery is removed. Thus, when the main battery is removed, the RTC is still supplied. Otherwise, user will
have to set the date and time after the next start.
With external BACKUP:
- if VBAT < VBACKUP, internal RTC is supplied by VBACKUP.
- if VBAT > VBACKUP, internal RTC is supplied by VBAT.
If there is no backup battery, VBACKUP input of the module has to be connected to VBAT signal.
Without external VBACKUP (VBACKUP input connected to VBAT)
- if VBAT > 2.2V, internal RTC is supplied by VBAT.
- if VBAT < 2.2V, internal RTC is not supplied.
Signal Min Max
VBACKUP +1.8V +3.2V
USB ID
VBUS
MO300 (device)
D +
D -
USB ID
VBUS
CMD
Host
D +
D -