912
SAM4CP [DATASHEET]
43051E–ATPL–08/14
Figure 40-6.
Non-optimized Temperature Conversion
The temperature factor has a slow variation rate and is potentially different from other conversion channels. As a result,
the ADC Controller triggers the measurement differently when TEMPON is set in ADC_TEMPMR but CH7 is not set in
the ADC_CHSR.
Under these conditions, the measurement is triggered every second by means of an internal trigger generated by RTC,
always enabled and totally independent of the internal/external triggers. The RTC event will be taken into account on the
next internal/external trigger event as described in
Figure 40-7, "Optimized Temperature Conversion combined with
classical conversions"
. The internal/external trigger is selected through the TRGSEL field of ADC_MR.
In this mode of operation, the temperature sensor is only powered for a period of time covering the startup time and
conversion time (refer to
Figure 40-8, "Temperature Conversion Only"
for more details).
Every second, a conversion is scheduled for channel 7 but the result of the conversion is only uploaded in ADC_CDR7
and not in ADC_LCDR. Therefore there is no change in the structure of the Peripheral DMA Controller buffer due to the
conversion of the temperature channel; only the enabled channels are kept in the buffer. The end of conversion of the
temperature channel is reported by means of EOC7 flag in ADC_ISR.
Base Address (BA)
BA + 0x02
ADC_CDR[TEMP]
0
ADC_CDR[0]
0
ADC_CDR[0]
0
BA + 0x04
ADC_CDR[0]
0
ADC_CDR[TEMP]
0
ADC_CDR[TEMP]
0
BA + 0x06
BA + 0x08
BA + 0x0A
Assu
m
ing ADC_CHSR[0] = 1 and ADC_CHSR[TEMP] = 1
where TEMP is the inde
x
of the te
m
perature sensor channel
trig.event1
DMA Buffer
Structure
trig.event2
DMA Transfer
trig.event3
ADC_SEL
C T
C
T
T
C
T
C
C: Classic ADC Conversion Sequence - T: Te
m
perature Sensor Channel
C
T
ADC_CHSR[TEMP]= 1 and ADC_MR.TRGEN=1
ADC_CDR[TEMP]
T1
T2
T0
ADC_CDR[0]
C0
C1
C2
C3
C4
C5
T3
T4
T5
ADC_LCDR
C0
C1
C2
C3
C4
T1
T2
T0
T3
T4
T5
Internal/E
x
ternal
Trigger event
(TRGSEL defined)