SBAS492 – JULY 2015
Figure 122. Ch n Low Threshold LSB Registers
7
6
5
4
3
2
1
0
CHn_LT[3:0]
0
0
0
0
R/W-0h
R-0h
R-0h
R-0h
R-0h
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 25. Channel n Low Threshold MSB Register Field Descriptions
(n = 0 to 7 for the ADS8668; n = 0 to 3 for the ADS8664)
Bit
Field
Type
Reset
Description
7-4
CH
n
_LT[7-4]
R/W
0h
These bits set the LSB for the 12-bit channel
n
low alarm.
(n = 0 to 7 for the ADS8668;
For example, bits 3-0 of the channel 0 register (address 19h) set
n = 0 to 3 for the ADS8664)
the LSB for the channel 0 low alarm threshold. The channel 0
low alarm threshold is AAF0h when bits 7-0 of the ch 0 low
threshold MSB register (address 18h) are set to AAh and bits 3-
0 of the ch 0 low threshold LSB register (address 19h) are set to
1111.
0000 = LSB is 0h
0001 = LSB is 01h
0010 to 1110 = LSB is 2h to Eh
1111 = LSB is Fh
3-0
CH
n
_LT[3-0]
R
0h
Read-only bit; internally set to 0
(n = 0 to 7 for the ADS8668;
n = 0 to 3 for the ADS8664)
8.5.2.3.6
Command Read-Back Register (address = 3Fh)
This register allows the device mode of operation to be read. On execution of this command, the device outputs
the command word executed in the previous data frame. The output of the command register appears on SDO
from the 16th falling edge onwards in an MSB-first format. All information regarding the command register is
contained in the first eight bits and the last eight bits are 0 (see
), thus the command read-back operation
can be stopped after the 24th SCLK cycle.
Figure 123. Command Read-Back Register
7
6
5
4
3
2
1
0
COMMAND_WORD[15:8]
R-0h
LEGEND: R = Read only; -n = value after reset
Table 26. Command Read-Back Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
COMMAND_WORD[15:8]
R
0h
Command executed in previous data frame.
64
Copyright © 2015, Texas Instruments Incorporated
Product Folder Links: