Rainbow Electronics MX7705 - Manual (Page 23)

ZERO: (Default = 0) Zero Bit. This is a read-only bit.
Values written to this bit are ignored.
CLKDIS: (Default = 0) Clock-Disable Bit. Set CLKDIS =
1 to disable the clock when using a crystal or resonator
across CLKIN and CLKOUT. Set CLKDIS = 1 to disable
CLKOUT when using a CMOS clock source at CLKIN.
CLKOUT is held low during clock disable to save
power. Set CLKDIS = 0 to allow other devices to use
the output signal on CLKOUT as a clock source and/or
to enable the external oscillator.
CLKDIV: (Default = 0) Clock-Divider Control Bit. The
MX7705 has an internal clock divider. Set this bit to 1 to
divide the input clock by two. When this bit is set to 0, the
MX7705 operates at the external oscillator frequency.
CLK: (Default = 1) Clock Bit. Set CLK = 1 for f
CLKIN
=
2.4576MHz with CLKDIV = 0, or 4.9152MHz with
CLKDIV = 1.
MX7705
16-Bit, Low-Power, 2-Channel,
Sigma-Delta ADC
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Table 6. Communications Register
FIRST BIT (MSB) (LSB)
FUNCTION
COMMUNICATION
START/DATA READY
REGISTER SELECT
READ/WRITE
SELECT
POWER-DOWN
MODE
CHANNEL SELECT
Name 0/DRDY RS2 RS1 RS0 R/W PD CH1 CH0
Defaults 0 0 0 0 0 0 0 0
Table 7. Register Selection
RS2 RS1 RS0 REGISTER POWER-ON RESET STATUS REGISTER SIZE (BITS)
0 0 0 Communications Register 0x00 8
0 0 1 Setup Register 0x01 8
0 1 0 Clock Register 0x05 8
0 1 1 Data Register N/A 16
1 0 0 Test Register* N/A 8
1 0 1 No Operation — —
1 1 0 Offset Register 0x1F 40 00 24
1 1 1 Gain Register 0x57 61 AB 24
Table 8. Channel Selection
CH1 CH0 AIN+ AIN-
OFFSET/GAIN
REGISTER PAIR
0 0 AIN1+ AIN1- 0
0 1 AIN2+ AIN2- 1
1 0 AIN1- AIN1- 0
1 1 AIN1- AIN2- 2
*The test register is used for factory testing only.
Table 9. Setup Register
FIRST BIT (MSB) (LSB)
FUNCTION MODE CONTROL PGA GAIN CONTROL
BIPOLAR/UNIPOLAR
MODE
BUFFER ENABLE FSYNC
Name MD1 MD0 G2 G1 G0 B/U BUF FSYNC
Defaults 0 0 0 0 0 0 0 1