Register Maps - Texas Instruments ADS867 Series Manual

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8.5 Register Maps

The internal registers of the ADS8674 and ADS8678 are categorized into two categories: command registers and
program registers.
The command registers are used to select the channel sequencing mode (AUTO_RST or MAN_Ch_n), configure
the device in standby (STDBY) or power-down (PWR_DN) mode, and reset (RST) the program registers to their
default values.
The program registers are used to select the sequence of channels for AUTO_RST mode, select the SDO output
format, control input range settings for individual channels, control the ALARM feature, reading the alarm flags,
and programming the alarm thresholds for each channel.
8.5.1 Command Register Description
The command register is a 16-bit, write-only register that is used to set the operating modes of the ADS8674 and
ADS8678. The settings in this register are used to select the channel sequencing mode (AUTO_RST or
MAN_Ch_n), configure the device in standby (STDBY) or power-down (PWR_DN) mode, and reset (RST) the
program registers to their default values. All command settings for this register are listed in
power-up or reset, the default content of the command register is all 0's and the device waits for a command to
be written before being placed into any mode of operation. See
16-bit command into the device. The device executes the command at the end of this particular data frame when
the CS signal goes high.
REGISTER
Continued Operation
(NO_OP)
Standby
(STDBY)
Power Down
(PWR_DN)
Reset program registers
(RST)
Auto Ch. Sequence with Reset
(AUTO_RST)
Manual Ch 0 Selection
(MAN_Ch_0)
Manual Ch 1 Selection
(MAN_Ch_1)
Manual Ch 2 Selection
(MAN_Ch_2)
Manual Ch 3 Selection
(MAN_Ch_3)
Manual Ch 4 Selection
(1)
(MAN_Ch_4)
Manual Ch 5 Selection
(MAN_Ch_5)
Manual Ch 6 Selection
(MAN_Ch_6)
Manual Ch 7 Selection
(MAN_Ch_7)
Manual AUX Selection
(MAN_AUX)
(1) Shading indicates bits or registers not included in the 4-channel version of the device.
Copyright © 2015, Texas Instruments Incorporated
Table 6. Command Register Map
MSB BYTE
B15 B14 B13 B12 B11 B10
0 0 0 0 0 0
1 0 0 0 0 0
1 0 0 0 0 0
1 0 0 0 0 1
1 0 1 0 0 0
1 1 0 0 0 0
1 1 0 0 0 1
1 1 0 0 1 0
1 1 0 0 1 1
1 1 0 1 0 0
1 1 0 1 0 1
1 1 0 1 1 0
1 1 0 1 1 1
1 1 1 0 0 0
Product Folder Links:
Figure 1 for a typical timing diagram for writing a
LSB BYTE
COMMAND
(Hex)
B9 B8 B[7:0]
0 0 0000 0000 0000h
1 0 0000 0000 8200h
1 1 0000 0000 8300h
0 1 0000 0000 8500h
0 0 0000 0000 A000h
0 0 0000 0000 C000h
0 0 0000 0000 C400h
0 0 0000 0000 C800h
0 0 0000 0000 CC00h
0 0 0000 0000 D000h
0 0 0000 0000 D400h
0 0 0000 0000 D800h
0 0 0000 0000 DC00h
0 0 0000 0000 E000h
ADS8674 ADS8678
ADS8674, ADS8678
SBAS627 – JULY 2015
Table 6. During
OPERATION IN NEXT FRAME
Continue operation in previous mode
Device is placed into standby mode
Device is powered down
Program register is reset to default
Auto mode enabled following a reset
Channel 0 input is selected
Channel 1 input is selected
Channel 2 input is selected
Channel 3 input is selected
Channel 4 input is selected
Channel 5 input is selected
Channel 6 input is selected
Channel 7 input is selected
AUX channel input is selected
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