Specifications

XT65/XT75 Hardware Interface Description
3.3 Power-Up / Power-Down Scenarios
s
XT65_XT75_HD_v01.001 Page 36 of 133 2007-1-8
Confidential / Released
Abbreviations used in the table:
3.3.3 Turn off XT65/XT75
XT65/XT75 can be turned off as follows:
• Normal shutdown: Software controlled by AT^SMSO command
• Automatic shutdown: Takes effect if board or battery temperature is out of range or if undervoltage or over-
voltage conditions occur.
3.3.3.1 Turn off XT65/XT75 Using AT Command
The best and safest approach to powering down XT65/XT75 is to issue the AT^SMSO command. This procedure
lets XT65/XT75 log off from the network and allows the software to enter into a secure state and safe data before
disconnecting the power supply. The mode is referred to as Power-down mode. In this mode, only the RTC stays
active.
Before switching off the device sends the following response:
^SMSO: MS OFF
OK
^SHUTDOWN
After sending AT^SMSO do not enter any other AT commands. There are two ways to verify when the module
turns off:
• Wait for the URC “^SHUTDOWN”. It indicates that data has been stored non-volatile and the module turns
off in less than 1 second.
• Also, you can monitor the PWR_IND pin. High state of PWR_IND definitely indicates that the module is
switched off.
Be sure not to disconnect the supply voltage V
BATT+
before the URC “^SHUTDOWN” has been issued and the
PWR_IND signal has gone high. Otherwise you run the risk of losing data. Signal states during turn-off are shown
in Figure 8.
DAI1 I Tristate I
DAI2 I Tristate O, L
DAI3 I Tristate O, L
DAI4 I Tristate I
DAI5 I Tristate I
DAI6 I Tristate I
L = Low output level
H = High output level
I = Input
O = Output
PD = Pull down with min +15µA and max. +100µA
PD(...k) = Fix pull down resistor
PU = Pull up with min -15µA and max. -100µA
PU(...k) = Fix pull up resistor
Table 6: Signal states
Signal name Undefined state
during startup
Defined state after
initialization
Active state after configuration by AT
command
GPIO SPI I
2
C DAI