Datasheet

REV. A
AD7719
–23–
Table XIII. Main ADC Control Register (AD0CON) Bit Designations (continued)
Bit Location Bit Name Description
AD0CON2 RN2 Main ADC Range Bits.
AD0CON1 RN1 Written by the user to select the main ADC input range as follows.
AD0CON0 RN0 RN2 RN1 RN0 Selected Main ADC Input Range (V
REF
= 2.5 V)
00 0±20 mV
00 1±40 mV
01 0±80 mV
01 1±160 mV
10 0±320 mV
10 1±640 mV
11 0±1.28 V
11 1±2.56 V
Aux ADC Control Registers (AD1CON):
(A3, A2, A1, A0 = 0, 0, 1, 1; Power-On Reset = 0x00)
The aux ADC control register is an 8-bit register from which data
can be read or to which data can be written. This register is used
to configure the aux ADC for range, channel selection, and uni-
polar or bipolar coding. Table XIV outlines the bit designations
for the aux ADC control register. AD1CON7 through AD1CON0
indicate the bit location, with AD1CON denoting that the bits
are in the aux ADC control register. AD1CON7 denotes the
first bit of the data stream. The number in parentheses indicates
the power-on/reset default status of that bit.
Table XIV. Aux ADC Control Register (AD1CON) Bit Designations
Bit Location Bit Name Description
AD1CON7 AD1EN Aux ADC Enable Bit.
Set by user to enable the Aux ADC. When set, the aux ADC operates according to the MD bits
in the mode register.
Cleared by the user to power down the aux ADC.
AD1CON6 ACH2 Aux ADC Channel Selection Bits.
AD1CON5 ACH1 Written by the user to select the active input channels used by the aux ADC as follows:
AD1CON4 ACH0
CHCON ACH2 ACH1 ACH0 Positive Input Negative Input
0000AIN3 AGND
0001AIN4 AGND
0010AIN5 AIN6
0011Temp Sensor (Temp Sensor Routed to the ADC Inputs)
0100AGND AGND (Internal Short)
1000AIN5 AGND
1001AIN6 AGND
1010AIN5 AIN6
1011Temp Sensor (Temp Sensor Routed to the ADC Inputs)
1100AGND AGND (Internal Short)
X101Not Defined
X110Not Defined
X111Not Defined
AD1CON3 U/B Aux ADC Unipolar/Bipolar Selection Bit.
Set by user to enable unipolar coding, i.e., zero differential input will result in 0x0000 output.
Cleared by user to enable bipolar coding, zero differential input will result in 0x8000 output.
AD1CON2 0 Must be zero for specified operation.
AD1CON1 0 Must be zero for specified operation.
AD1CON0 ARN Auxiliary Channel Input Range Bit.
When set by the user, the input range is ±REFIN2. When cleared by the user, the input range is ±REFIN2/2.
NOTES
1. When the temperature sensor is selected, the AD7719 automatically selects its internal reference. The temperature sensor is not factory calibrated. Temp sensor
is suitable for relative temperature measurements. The temperature sensor yields conversion results where a conversion result of 0x8000 equates to typically 0°C.
2. A 1°C change in temperature will normally result in a 256 LSB change in the AD1 data register (ADC conversion result).
7NOC1DA6NOC1DA5NOC1DA4NOC1DA3NOC1DA2NOC1DA1NOC1DA0NOC1DA
)0(NE1DA)0(2HCA)0(1HCA)0(0HCA/U B )0()0(0)0(0)1(NRA