1004
6437E–ATARM–23-Apr-13
SAM9M11
42.9
Conversion Triggers
Conversions of the active analog channels are started with a software or a hardware trigger.
1.
The hardware trigger can be selected by the filed TRGMOD in the TSADCC Trigger Register
(TSADCC_TRGR) between:
an edge, either rising or falling or any, detected on the external trigger pin TSADTRG
a continuous trigger, meaning the TSADCC restarts the next sequence as soon as it finishes
the current one, in this case, only one software trigger is required at the beginning
a periodic trigger, which is defined by programming the field TRGPER in the
“TSADCCEnabling hardware triggers does not disable the software trigger functionality. Thus, if a hard-
ware trigger is selected, the start of a conversion can still be initiated by the software trigger.
42.10 Operating Modes
The Touch Screen ADC Controller features several operating modes, each defining a conver-
sion sequence:
The ADC Mode: at each trigger, all the enabled channels are converted
The Touch Screen Mode: at each trigger, the touch screen inputs are converted with the
switches accordingly set and the results are processed and stored in the corresponding data
registers
The Interleaved Mode: at each trigger, the 8 conversions for the touch screen and the analog
inputs conversions are performed. Only the analog inputs results are managed by the PDC
and the touch screen conversions can be performed less often than the analog inputs.
The Operating Mode of the TSADCC is programmed in the field TSAMOD in the
“TSADCCThe conversion sequences for each Operating Mode are described in the following paragraphs.
The conversion sequencer, combined with the Sleep Modes, allows automatic processing with
minimum processor intervention and optimized power consumption. In any case, the sequence
starts with a trigger event.
Note:
The reference voltage pins always remain connected in normal mode as in sleep mode.
42.10.1
ADC Mode
possible.
At each trigger, the following sequence is performed:
3.
If SLEEP is set, wake up the ADC cell and wait for the Startup Time.
4.
If Channel 0 is enabled, convert Channel 0 and store result in both TSADCC_CDR0
and TSADCC_LCDR.