Analogue Control Interface

FX839

© 1997 Consumer Microcircuits Limited

13

D/839/4

DAC CONTROL Register (Hex address $D3)

This register controls the resolution and the number of enabled DAC outputs:

NBIT DAC1, NBIT DAC2, NBIT DAC3

(Bit 7 to Bit 5)

These bits define the input resolutions for each of the four DACs. When 'NBIT

DAC

When 'NBIT DAC

resolution of DAC

Bit 4

Reserved for future use. This bit should be set to '0'.

DAC1 ENABLE, DAC2 ENABLE, DAC3 ENABLE

(Bit 3 to Bit 1)

These bits allow any one or more of the three DACs to be powered up. When '0'

the DAC

is powered on and the output voltage is defined by the DAC Data Registers.

Bit 0

Reserved for future use. This bit should be set to '0'.

DAC1 DATA Register (Hex Address $D4)

DAC2 DATA Register (Hex Address $D5)

DAC3 DATA Register (Hex Address $D6)

The data in these three registers sets the analogue voltage at the output of DAC1, DAC2 and DAC3. This data

will consist of one or two bytes depending on the defined input resolution which is set by bits 7, 6 and 5 of the

DAC Control Register. When operating with 10-bit resolution Bit 7 to Bit 2 of the DAC

data byte must be set to "0".

ADC CONTROL Register (Hex Address $D7)

This register controls the resolution, active inputs and conversion modes of the ADC as described below:

Bit 7

Reserved for future use. This bit should be set to '0'.

Bit 6

Reserved for future use. This bit should be set to ‘1’.

(On reset, this bit is set to ‘0’).

READN

(Bit 5)

When this bit is set to '1' all active input channels are continuously sampled and

the latest converted data stored for each channel. When this bit is set to ‘0’ all

conversions are stopped so that they may be read.

ADC1 ACTIVE, ADC2 ACTIVE, ADC3 ACTIVE, ADC4 ACTIVE

(Bit 4 to Bit 1)

These bits allow any one or more of the four ADC input channels to be enabled.

When '0' the ADCIN

is defined as active and the input voltage is converted.

Note: ADC1 must always be enabled for any other channel to work.

(Bit 0)

Reserved for future use. This bit should be set to ‘0’.