DocID024597 Rev 5 551/1830
RM0351 Analog-to-digital converters (ADC)
614
These thresholds are programmed in bits HT1[11:0] and LT1[11:0] of the ADC_TR1 register
for the analog watchdog 1. When converting data with a resolution of less than 12 bits
(according to bits RES[1:0]), the LSB of the programmed thresholds must be kept cleared
because the internal comparison is always performed on the full 12-bit raw converted data
(left aligned).
Table 112 describes how the comparison is performed for all the possible resolutions for
analog watchdog 1.
Description of analog watchdog 2 and 3
The second and third analog watchdogs are more flexible and can guard several selected
channels by programming the corresponding bits in AWDCHx[19:0] (x=2,3).
The corresponding watchdog is enabled when any bit of AWDCHx[19:0] (x=2,3) is set.
They are limited to a resolution of 8 bits and only the 8 MSBs of the thresholds can be
programmed into HTx[7:0] and LTx[7:0]. Table 113 describes how the comparison is
performed for all the possible resolutions.
Table 112. Analog watchdog 1 comparison
Resolution
(bit
RES[1:0])
Analog watchdog comparison
between:
Comments
Raw converted data,
left aligned
(1)
1. The watchdog comparison is performed on the raw converted data before any alignment calculation and
before applying any offsets (the data which is compared is not signed).
Thresholds
00: 12-bit DATA[11:0]
LT1[11:0] and
HT1[11:0]
-
01: 10-bit DATA[11:2],00
LT1[11:0] and
HT1[11:0]
User must configure LT1[1:0] and HT1[1:0] to
00
10: 8-bit DATA[11:4],0000
LT1[11:0] and
HT1[11:0]
User must configure LT1[3:0] and HT1[3:0] to
0000
11: 6-bit
DATA[11:6],0000
00
LT1[11:0] and
HT1[11:0]
User must configure LT1[5:0] and HT1[5:0] to
000000
Table 113. Analog watchdog 2 and 3 comparison
Resolution
(bits RES[1:0])
Analog watchdog comparison between:
Comments
Raw converted data,
left aligned
(1)
Thresholds
00: 12-bit DATA[11:4] LTx[7:0] and HTx[7:0] DATA[3:0] are not relevant for the comparison
01: 10-bit DATA[11:4] LTx[7:0] and HTx[7:0] DATA[3:2] are not relevant for the comparison
10: 8-bit DATA[11:4] LTx[7:0] and HTx[7:0] -
11: 6-bit DATA[11:6],00 LTx[7:0] and HTx[7:0] User must configure LTx[1:0] and HTx[1:0] to 00
1. The watchdog comparison is performed on the raw converted data before any alignment calculation and before
applying any offsets (the data which is compared is not signed).
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