Digi Analog Features RCM4000 only, Table B-3. Positive A/D Converter Input Voltage Ranges

B.4.3 Analog Features (RCM4000 only)

The Prototyping Board has typical support circuitry installed to complement the ADS7870 A/D converter on the RCM4000 module (the A/D converter is not available on the RCM4010 module).

B.4.3.1 A/D Converter Inputs

Figure B-6shows a pair of A/D converter input circuits. The resistors form an approx. 9:1 attenuator, and the capacitor filters noise pulses from the A/D converter input. The 10 kΩ inline jumpers allow other configurations (see Table B-6) and provide digital isolation.

		Inline jumpers are
		10 kW resistors
100 kW					ADC
LN0_IN
				(RCM4100)
LN1_IN					ADC
100 kW
2.2 nF	2.2 nF	kW	kW
		10	10
				JP23/JP24BVREF =
				3	2.048 V
				1
AGND
Figure B-6. A/D Converter Inputs

The A/D converter chip can make either single-ended or differential measurements depending on the value of the opmode parameter in the software function call. Adjacent A/D converter inputs are paired to make differential measurements. The default setup on the Prototyping Board is to measure only positive voltages for the ranges listed in Table B-3.

Table B-3. Positive A/D Converter Input Voltage Ranges

Min. Voltage

(V)

Max. Voltage

(with prescaler)

(V)

A/D Converter

Gain

mV per Tick

0.0	+22.528	1	11
0.0	+11.264	2	5.5
0.0	+5.632	4	2.75
0.0	+4.506	5	2.20
0.0	+2.816	8	1.375
0.0	+2.253	10	1.100
0.0	+1.408	16	0.688
0.0	+1.126	20	0.550

100 RabbitCore RCM4000