These two registers are applicable to
the ADS1115 and ADS1114. These registers serve no purpose in the
ADS1113. The upper and lower threshold
values used by the comparator are stored in two 16-bit registers in 2's complement
format. The comparator is implemented as a digital comparator; therefore, the values
in these registers must be updated whenever the PGA settings are changed.
The conversion-ready function of the
ALERT/RDY pin is enabled by setting the Hi_thresh register MSB to 1b and the
Lo_thresh register MSB to 0b. To use the comparator function of the ALERT/RDY pin,
the Hi_thresh register value must always be greater than the Lo_thresh register
value. The threshold register formats are shown in Figure 8-6. When set to RDY mode, the ALERT/RDY pin outputs the OS bit when in single-shot
mode, and provides a continuous-conversion ready pulse when in continuous-conversion
mode.
Figure 8-6 Lo_thresh
Register
15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
Lo_thresh[15:8] |
R/W-80h |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
Lo_thresh[7:0] |
R/W-00h |
LEGEND: R/W = Read/Write; R = Read only; -n = value
after reset |
Table 8-4 Hi_thresh Register
15 |
14 |
13 |
12 |
11 |
10 |
9 |
8 |
Hi_thresh[15:8] |
R/W-7Fh |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
Hi_thresh[7:0] |
R/W-FFh |
LEGEND: R/W = Read/Write; R = Read only; -n = value
after reset |
Table 8-5 Lo_thresh
and Hi_thresh Register Field Descriptions
Bit |
Field |
Type |
Reset |
Description |
15:0 |
Lo_thresh[15:0] |
R/W |
8000h |
Low threshold value |
15:0 |
Hi_thresh[15:0] |
R/W |
7FFFh |
High threshold value |