MC45 Hardware Interface Description
P R E L I M I N A R Y
MC45_HD_01_V00.02a
Page 34 of 90
12.08.2002
3.3.1.2 Timing of the ignition process
When designing your application platform take into account that powering up MC45 requires
the following steps.
·
The ignition line cannot be operated until V
BATT+
passes the level of 3.0V.
·
10ms after V
BATT+
has reached 3.0V the ignition line can be switched low. The duration of
the falling edge must not exceed 1ms.
·
Another 100ms are required to power up the module.
·
Ensure that V
BATT+
does not fall below 3.0V while the ignition line is driven. Otherwise the
module cannot be activated.
·
If the VDDLP line is fed from an external power supply as explained in Chapter 3.4, the
/IGT line is HiZ before the rising edge of BATT+.
Figure 7: Timing of power-on process if VDDLP is not used
Figure 8: Timing of power-on process if VDDLP is fed from external source
3.0V
0V
VBATT+
min. 100ms
max. 1ms
10ms
/IGT
HiZ
HiZ
3.0V
0V
VBATT+
min. 100ms
max. 1ms
10ms
/IGT
HiZ
HiZ
