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TMP92CZ26A
92CZ26A-607
3.23.2.3 Starting an AD Conversion
The ADC supports two types of AD conversion: normal AD conversion and
high-priority AD conversion. The ADC initiates a normal AD conversion by software
when the ADMOD0<ADS> is set to “1”. It initiates a high-priority AD conversion by
software when the ADMOD2<HADS> is set to “1”. For a normal AD conversion,
ADMOD1<REPEAT, SCAN> select one of four conversion modes. For a high-priority
AD conversion, the ADC only supports Fixed-Channel Single Conversion mode.
The ADMOD0<TSEL1:0> and ADMOD2<HTSEL1:0> enable a hardware trigger for
a normal and high-priority AD conversion, respectively. When these bits are set to “10”,
a normal or high-priority AD conversion is triggered by a falling edge applied to
ADTRG pin. When ADMOD0<TSEL1:0> is set to “00”, a normal AD conversion is
triggered by INTTB00 of 16-Bit Timer interrupt. When ADMOD2<HTSEL1:0> is set
to “00”, a high-priority AD conversion is triggered by INTTB10 of 16-Bit Timer
interrupt. If this bit is “11”, it is triggered by I2S sampling block. Even when a
hardware trigger is enabled, software starting can be used.
When a normal AD conversion starts, the Busy flag (ADMOD0<BUSY>) is set to “1”.
When a high-priority AD conversion starts, the high-priority AD conversion busy flag
(ADMOD2<HBUSY>) is set to “1”. During a normal AD conversion, if a high-priority
AD conversion start, ADMOD0<BUSY> holds “1”.
When an AD conversion complete, ADMOD0<EOS> and ADMOD2<HEOS> is set to
“1”. These flags are cleared to “0” by reading these flags only.
During a normal AD conversion, writing a “1” to ADMOD0<ADS> causes the ADC
to abort any ongoing conversion immediately, and restart.
During a normal AD conversion, if normal AD conversion starting is enabled by
hard ware trigger, normal AD conversion is restarted when start condition from hard
ware trigger is satisfied. When restart is set, normal AD conversion is aborted
immediately.
During a normal AD conversion, if a high-priority AD conversion starts(writing a “1”
to ADMOD2<HADS> or a hard ware trigger occurs), the ADC aborts any ongoing
conversion immediately, and then start a high-priority AD conversion for the channel
specified by ADMOD3<HADCH2:0>. Upon the completion of the high-priority
conversion, the ADC stores the conversion result to ADREGSPH/L, and then resumes
the suspended normal conversion with that channel.
Note: It cannot overlap with three or more AD conversions.
Prohibition example 1 : In FIRST normal AD conversion
Æ (Before finished FIRST normal AD conversion) Started SECOND normal AD conversion
Æ (Before finished SECOND normal AD conversion) Started THIRD normal AD conversion
Prohibition example 2 : In FIRST normal AD conversion
Æ (Before finished FIRST normal AD conversion) Started SECOND normal AD conversion
Æ (Before finished SECOND normal AD conversion) Started THIRD high-priority AD conversion