Atmel QTouch Library User Guide

Figure 37 QMatrix method schematicQMatrix method hardware resource requirement for UC3LThe clock for the CAT module, CLK_CAT, is generated by the Power Manager (PM). This clock isturned on by default, and can be enabled and disabled in the PM. The user must ensure thatCLK_CAT is enabled before initializing the QTouch Library.QMatrix operations also require the CAT generic clock, GCLK_CAT. This generic clock isgenerated by the System Control Interface (SCIF), and is shared between the CAT and theAnalog Comparator Interface. The user must ensure that the GCLK_CAT is enabled in the SCIFbefore using QMatrix functionality. For proper QMatrix operation, the frequency of GCLK_CATmust be less than one fourth the frequency of CLK_CAT.For QMatrix operation, the Analog comparators channels are used (using the ACIFB interface)depending on the Y Lines enabled. See Note 4 in Section 6.3.7.4.The QMatrix method acquisition using the CAT module requires two Peripheral DMA channelsthat must be provided by the application.QMatrix method Channel and Sensor numbering for UC3LX0Ch 0Ch 4Sensor1Ch 8Ch 12X1X2Ch 1Ch 2Sensor 0Ch 5Ch 6Sensor2Sensor3Ch 9Ch 10Sensor 5Ch 13Ch 14Sensor 6ROTOR/SLIDERX3Ch 3Ch 7Sensor4Ch 11Ch 15Yk0 Yk1 Yk2 Yk3Figure 38 QMatrix channel numbering for UC3LKEYThe above figure represents a typical 4 X 4 matrix of QMatrix sensor arrangement along with thechannel numbers. The Channel numbering starts with Channel 0 (Ch0) and increase sequentiallyfrom Ch0 to Ch15. Similarly the Sensor numbering starts with Sensor 0. The Channel numbersignifies the order in which the QTouch Library stores the acquisition data in the memory.Note: The touch_qm_sensor_config API must follow the above Channel and Sensor numberingwhen configuring the Sensors.1228207K-AT42-09/11