A/D Interface; General Purpose A/D; Power Supply A/D; Gpad Specifications - Motorola 8900 - Blackberry Curve Cell Phone OEM Car Charger Developer's Manual

A/D Interface

A/D Interface
The C24 includes 4 Analog to Digital Converter (ADC) signals with 8-bit resolution, for
environmental and electrical measurements. The ADC signals measure an analog DC voltage
level on their inputs which is converted to an 8-bit digital value for further processing by C24 or
the user application.
The A/D signals operation and reporting mechanism is defined by the AT+MMAD command.
Table 2-16

General Purpose A/D

The C24 provides 3 general purpose A/D (GPAD) signals for customer application use. Each A/D
signal can monitor a separate external voltage and report its measured level independently to the
application, through the AT command interface.
The GPAD signals measure a DC voltage level of 0.1 - 2.5 V, which is converted internally to a
8-bit digital value. The user application can monitor the A/D voltage level through the
AT+MMAD command, which returns the measured DC level in Volts times 100.
For example, a measured analog DC level of 1.75 Volts will be presented as 175 by the MMAD
command.
Table 2-17

Power Supply A/D

The main power supply (VCC) is constantly monitored internally by the C24 through a dedicated
A/D signal, which is not accessible on the interface connector.
38
below, lists the internal and external A/D signals provided by C24.
Table 2-16: A/D Signals
ADC Name Description
VCC Power Supply A/D
ADC3 GPAD 3
ADC2 GPAD 2
ADC1 GPAD 1
gives the GPAD specifications.
Table 2-17: GPAD Specifications
Parameter Conditions
Maximum Operating range
Input Voltage
Measurement ADC range
Voltage
Resolution
C24 Module Hardware Description
ADC
Pin # # Min Max
- 5 3.0 4.5
47 3 0.1 2.5
43 2 0.1 2.5
37 1 0.1 2.5
Min Typ Max Unit
0 2.75 V
0.1 2.5 V
10 mV
Unit
V
V
V
V
December 15, 2008