Integration Manual

HMS1 Hardware Interface Description
Confidential / Preliminary
s
HMS1_HD_V01.62 Page 28 of 39 2006-08-21
Table 10: Signal description
Function Signal name IO Signal form and level Comment
V
BATT
= 3.6V±5%
I ≈ 2A, during Tx burst (GSM)
Power
supply
BATT+ I
n Tx = n x 577µs peak current every
4.616ms
Five pins of BATT+ and GND
must be connected in parallel
for supply purposes because
higher peak currents may
occur.
Minimum voltage must not fall
below 3.3V including drop,
ripple, spikes.
Power
supply
GND Ground Application Ground
External
supply
voltage
VEXT O
Normal mode:
V
O
min = 2.70V
V
O
typ = 2.85V
V
O
max = 3.00V
I
O
max = Tbd.
VEXT may be used for
application circuits, for
example to supply power for
an SD card.
If unused keep pin open.
The external digital logic must
not cause any spikes or
glitches on voltage VEXT.
Power
indicator
PWR_IND O V
IH
max = Tbd.
V
OL
max = Tbd. at Imax = Tbd.
PWR_IND (Power Indicator)
notifies the module’s on/off
state.
PWR_IND is an open
collector that needs to be
connected to an external pull-
up resistor. Low state of the
open collector indicates that
the module is on. Vice versa,
high level notifies the Power-
down mode.
Therefore, the pin may be
used to enable external
voltage regulators which
supply an external logic for
communication with the
module, e.g. level converters.
Ignition IGT I
Internal pull-up: R
I
≈ 200kΩ
V
IL
max = Tbd. at Imax = Tbd.
V
OH
max = Tbd.
ON
~~~
|____|
~~~
Active Low ≥ 400ms
(to be verified)
This signal switches on the
module.
This line must be driven low
by an open drain or open
collector driver.
Emergency
reset
EMERG_RST I
Internal pull-up.
V
IL
max = 0.2V at Imax = -0.2mA
Signal
~~~
|______|
~~~
Pull down ≥ Tbd.
Reset in case of emergency.
This line must be driven low
by open drain or open
collector.
If unused keep pin open.