BGS3 Hardware Interface Description
3.3 Power Up / Power Down Scenarios
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BGS3_HD_v01.000d
Page 26 of 109
2010-03-26
Confidential / Released
3.3
Power Up / Power Down Scenarios
In general, be sure not to turn on BGS3 while it is beyond the safety limits of voltage and tem-
perature stated in
. BGS3 would immediately switch off after having started and de-
tected these inappropriate conditions. In extreme cases this can cause permanent damage to
the module.
3.3.1
Turn on BGS3
BGS3 can be started in a variety of ways as described in the following chapters:
•
Hardware driven start-up by IGT line: starts Normal mode (see
•
Software controlled reset by AT+CFUN command: starts Normal mode (see
)
•
Hardware driven start-up by VCHARGE line: starts charging algorithm and charge-only
mode (see
)
After startup or mode change the following URCs indicate the module’s ready state:
•
“SYSSTART” indicates that the module has entered Normal mode.
•
^SYSSTART CHARGE ONLY MODE” indicates that the module has entered the Charge-
only mode.
These URCs are indicated only if the module is set to a fixed bit rate, i.e. they do not appear if
autobauding is enabled (AT+IPR
0). Detailed explanations on AT+CFUN and AT+IPR can be
3.3.1.1
Turn on BGS3 Using Ignition Line IGT
When the BGS3 module is in Power-down mode or Charge-only mode, it can be started to Nor-
mal mode by driving the IGT (ignition) line to ground. This must be accomplished with an open
drain/collector driver to avoid current flowing into this line.
The module will start up when both of the following two conditions are met:
•
The supply voltage applied at BATT+ must be in the operating range.
•
The IGT line needs to be driven low for at least 400ms in Power-down mode or at least 2s
in Charge-only mode.
Considering different strategies of host application design the figures below show two ap-
proaches to meet this requirement: The example in
assumes that IGT is activated after
BATT+ has already been applied. The example in
assumes that IGT is held low before
BATT+ is switched on. In either case, to power on the module, ensure that low state of IGT
takes at least 400ms (Power-down mode) or 2s (Charge-only mode) from the moment the volt-
age at BATT+ is available. For Charge-only mode see also
.
Assertion of CTS indicates that the module is ready to receive data from the host application.
In addition, if configured to a fixed bit rate (AT+IPR
0), the module will send the URC
“^SYSSTART” which notifies the host application that the first AT command can be sent to the
module. The duration until this URC is output varies with the SIM card and may take a couple
of seconds.
Please note that no “^SYSSTART” URC will be generated if autobauding (AT+IPR=0) is en-
abled.
