101-0522 Rabbit Semiconductor, 101-0522 Datasheet - Page 103

• Manufacturer Part Number: 101-0522
• Description: MODULE RABBITCORE RCM3220
• Manufacturer: Rabbit Semiconductor

Specifications of 101-0522

• Module/board Type: MPU Core Module
• For Use With/related Products: RCM3220
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 101-522; 101-522

B.1.5.3 Other A/D Converter Features
The A/D converter’s internal reference voltage is software-configurable for 1.15 V, 2.048 V,
or 2.5 V using the
library. The scaling circuitry on the Prototyping Board and the sample programs are
optimized for an internal reference voltage of 2.048 V. This internal reference voltage is
available on pin 3 of shrouded header J8 as VREF, and allows you to convert analog input
voltages that are negative with respect to analog ground.
The A/D converter’s CONVERT pin is available on pin 2 of shrouded header J8, and can
be used as a hardware means of forcing the A/D converter to start a conversion cycle. The
CONVERT signal is an edge-triggered event and has a hold time of two CCLK periods for
debounce.
A conversion is started by an active (rising) edge on the CONVERT pin. The CONVERT
pin must stay low for at least two CCLK periods before going high for at least two CCLK
periods. Figure B-7 shows the timing of a conversion start. The double falling arrow on
CCLK indicates the actual start of the conversion cycle.
RabbitCore RCM3700 User’s Manual
NOTE: The amplifier inside the A/D converter’s internal voltage reference circuit has a
very limited output-current capability. The internal buffer can source up to 20 mA and
sink only up to 20 µA. A separate buffer amplifier at U7 supplies the load current.
Figure B-7. Timing Diagram for Conversion Start Using CONVERT Pin
#define AD_OSC_ENABLE
macro in the Dynamic C
RCM37xx.LIB
101