Enfora Enabler III-G
Modem Integration Guide
Output Levels
Parameter/Conditions
Min
Typ
Max
Units
Serial Interface Input
High RXD Input High On
D-
I
SOURCE
= 4 mA
2.4
3.3 3.6
Vdc
Serial Interface Input
Low RXD Input Low On
D-
I
SOURCE
= -4 mA
0.0
0.1 0.4
Vdc
USB port / Audio mode
Terminations Parameter/Conditions Min
Typ
Max
Units
Phone Microphone Input
Impedance
Freq = 1 kHz
10
k
Ω
Phone Speaker Output
impedance
Freq = 1 kHz
200
Ω
Current
Phone Speaker Source
Current
D
±
grounded
20
mA
Input Levels
Phone Microphone Input
Range
1.0
2.2
V
Output Levels
Phone Speaker Output Bias
0.7
1.6
V
Phone Speaker Output Range
2.2
V
6.6.6. LED A (Pin 8) & B (Pin 6), VRWLED (Pin 10)
Pin Name
Pin Number
Signal Direction
Description
LED A
8
I
LED A open drain input
LED B
6
I
LED B open drain input
The LED ‘driver’ pins are able to operate as a general current sink, or use in conjunction with the built in
LED driver VRWLED.
Two white-LEDs drivers are available from the module.
The first driver, “LED_A” is dedicated for the screen backlight and can drive up to four white-LEDs in
series.
The second driver, “LED_B” is dedicated for the keypad and can drive up to four white-LEDs in series.
The two white-LEDs driver series are fed by a dedicated DC-DC step-up regulator VRWLED.
The maximum current delivered by this white-LEDs drivers is 63.75 mA, in order to have an average
maximum current within each white-LED of 21.25 mA . The 63.75 mA is switched among the three series
of LEDs as described in the below table, the corresponding timing scheme is reported in the below table.
Each series of LEDs has a maximum average current per frame of 21.25 mA (
3
75
.
63
mA
). The frame
period is 3
×
T
CK
. T
CK
can be programmed via a register between 2 ms and 6 ms.
The current delivered to each series of white-LEDs is obtained from a dedicated 8-bit DAC-based system.
While the 4-LSBs contribution is generated starting from a PWM signal that modulates a 4 mA current
level as indicated in the below table.
GSM0308PB001
39
Version DRAFT – 2/9/2007
