65.6.17.2 Touchscreen Channels Only

When only touchscreen conversions are required (i.e., TSMODE ≠ 0 in ADC_TSMR and ADC_CHSR equals 0), the structure of data within the buffer is defined by ADC_TSMR.

When TSMODE = 1 or 3, each trigger event adds two half-words in the buffer (assuming TSAV = 0), first half-word being ADC_XPOSR.XPOS, then ADC_YPOSR.YPOS. If TSAV/TSFREQ ≠ 0, the data structure remains unchanged. Not all trigger events add data to the buffer.

When TSMODE = 2, each trigger event adds four half-words to the buffer (assuming TSAV = 0), first half-word being ADC_XPOSR.XPOS, followed by ADC_YPOSR.YPOS and finally ADC_PRESSR.Z1, followed by ADC_PRESSR.Z2.

When ADC_EMR.TAG is set, the CHNB field (four most significant bits of ADC_LCDR) is cleared when ADC_XPOSR.XPOS is transmitted and set when ADC_YPOSR.YPOS is transmitted, allowing an easier post-processing of the buffer or a better checking of the buffer integrity. In case 4-wire with Pressure mode is selected, the Z1 value is transmitted to the buffer along with tag set to 2 and Z2 is tagged with value 3.

XSCALE and YSCALE (calibration values) are not transmitted to the buffer because they are supposed to be constant and moreover only measured at the very first startup of the controller or upon user request.

There is no change in buffer structure whatever the value of PENDET.ADC_TSMR, but it is recommended to use the pen detection function for buffer postprocessing (see Pen Detection Status).

Figure 65-22. Buffer Structure When Only Touchscreen Channels are Enabled