Datasheet

Data Sheet AD7877
Rev. D | Page 35 of 44
DETAILED REGISTER DESCRIPTIONS
Register Name: Control Register 1
Write Address: 0001
Read Address: 00001
Default Value: 0x000
Type: Read/write
Table 16.
Bit Name Read/Write Description
0 MODE0 R/W LSB of ADC mode code
1
MODE1
R/W
MSB of ADC mode code
00 = no conversion
01 = single conversion
10 = conversion sequence (slave mode)
11 = conversion sequence (master mode)
2 RD0 R/W LSB of register read address; to read a register, its address must first be written to Control Register 1
3 RD1 R/W Bit 1 of register read address; to read a register, its address must first be written to Control Register 1
4 RD2 R/W Bit 2 of register read address; to read a register, its address must first be written to Control Register 1
5 RD3 R/W Bit 3 of register read address; to read a register, its address must first be written to Control Register 1
6 RD4 R/W MSB of register read address; to read a register, its address must first be written to Control Register 1
7 CHADD0 R/W LSB of ADC channel address
8 CHADD1 R/W Bit 1 of ADC channel address
9 CHADD2 R/W Bit 2 of ADC channel address
10 CHADD3 R/W MSB of ADC channel address
0000 = X+ input (Y position)
0001 = Y+ input (X position)
0010 = Y− (Z2) input (used for touch-pressure calculation)
0011 = Auxiliary Input 1 (AUX1)
0100 = Auxiliary Input 2 (AUX2)
0101 = Auxiliary Input 3 (AUX3)
0110 = Battery Monitor Input 1 (BAT1)
0111 = Battery Monitor Input 2 (BAT2)
1000 = Temperature Measurement 1 (used for single conversion)
1001 = Temperature Measurement 2 (used for differential measurement method)
1010 = X+ (Z1) input (used for touch-pressure calculation)
11
SER/
DFR
R/W Selects normal (single-ended) or ratiometric (differential) conversion
0 = ratiometric (differential)
1 = normal (single-ended)