MPC5604B/C Microcontroller Reference Manual, Rev. 8
Freescale Semiconductor 601
Three presampling value fields, one per channel type, in the PSCR make it possible to select different
presampling values for each type.
25.3.6 Programmable analog watchdog
25.3.6.1 Introduction
The analog watchdogs are used for determining whether the result of a channel conversion lies within a
given guarded area (as shown in Figure 25-7) specified by an upper and a lower threshold value named
THRH and THRL respectively.
Figure 25-7. Guarded area
After the conversion of the selected channel, a comparison is performed between the converted value and
the threshold values. If the converted value lies outside that guarded area then corresponding threshold
violation interrupts are generated. The comparison result is stored as WTISR[WDGxH] and
WTISR[WDGxL] as explained in Table 25-5. Depending on the mask bits WTIMR[MSKWDGxL] and
WTIMR[MSKWDGxH], an interrupt is generated on threshold violation.
The channel on which the analog watchdog is to be applied is selected by the TRC[THRCH]. The analog
watchdog is enabled by setting the corresponding TRC[THREN].
Table 25-4. Presampling voltage selection based on PREVALx fields
PSCR[PREVALx] Presampling voltage
00 V0 = V
SS_HV_ADC
01 V1 = V
DD_HV_ADC
10 Reserved
11 Reserved
Table 25-5. Values of WDGxH and WDGxL fields
WDGxH WDGxL Converted data
1 0 converted data > THRH
0 1 converted data < THRL
0 0 THRL <= converted data <= THRH
THRH
THRL
Analog voltage
Upper threshold
Lower threshold
Guarded area
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