57.6.16.4 Pen Detection Status

If the pen detection measure is enabled (ADC_TSMR.PENDET is set), the XPOS, YPOS, Z1, Z2 values transmitted to the buffer through ADC_LCDR are cleared (including the CHNB field), if the ADC_ISR.PENS flag is 0. When the ADC_ISR.PENS flag is set, XPOS, YPOS, Z1, Z2 are normally transmitted.

Therefore, using pen detection together with tag function eases the post-processing of the buffer, especially to determine which touchscreen converted values correspond to a period of time when the pen was in contact with the screen.

When the pen detection is disabled or the tag function is disabled, XPOS, YPOS, Z1, Z2 are normally transmitted without tag and no relationship can be found with pen status, thus post-processing may not be easy.