Specifications

TC35 / TC37 Hardware Interface Description
TC35_37_HD_02_V03.10 - Released Page 30 of 92 21.12.2001
3.3 Power up / down scenarios
3.3.1 Turn on the GSM engine
TC35 and TC37 modules can be activated in a variety of ways which are described in the
following chapters:
• via ignition line IGT: starts normal operating state (see Chapters 3.3.1.1 and 3.3.1.2)
• via POWER lines: starts charging algorithm (see Chapters 3.2.2.3 and 3.3.1.3)
• via RTC interrupt: starts Alarm mode (see Chapter 3.3.1.4)
3.3.1.1 Turn on GSM engine using the ignition line IGT (Power on)
To switch on TC35/TC37 the IGT (Ignition) signal needs to be driven to ground level for at
least 100ms. This can be accomplished using an open drain/collector driver in order to avoid
current flowing into this pin.
Figure 7: Power-on by ignition signal
In a battery operated TC35 or TC37 application, the duration of the /IGT signal must be 1s
minimum when the charger is connected and you may want to go from charging to Normal
mode.
Internal reset
ca. 180ms
generated by GSM engine
/PD
max. 900ms
RS-232
interface
undefined
defined
VDD
/TXD0
50 to
100ms
VBATT+
/IGT
min. 10ms
min.
100ms
HiZ
HiZ
For details please see Chapter 3.3.1.2