When using the QTouch technology each channel uses two I/O pins, one named SNS and the other named SNSK. The two pins for a single channel can be on the same I/O port or they can be split between two different ports. In both cases, the ports selected for SNS and SNSK pins are called a port pair - even if it's the same port. When selecting different ports for SNS and SNSK it's called an inter-port pair, when selecting the same port for both SNS and SNSK it's called an intra-port pair.
Inter-port pairs support as many channels as there are pins on the ports. For example, an inter-port pair consisting of two 8-pin ports will support 8 channels (two pins, SNS and SNSK, for each channel). Intra-port pairs will only support half as many channels as there are pins on the ports. For example, an intra-port pair using a 8 pin port will support 4 channels. This means that 8 channels can be supported either through selecting one single inter-port pair using different SNS and SNSK ports, or through two intra-port pairs each using the same port for SNS and SNSK pins.
If using two port pairs, the different sensors and their corresponding channels can be assigned between them, but the assignment must be in a consecutive order. The first set of sensors will be assigned to the first port pair and the last set of sensors (selectable how many should be part of the group) will be assigned to the second port pair. Use the up- and down-arrow buttons to a sensor down or up between the two port pairs.
QTouch Sensor-Port Selection Guidelines:
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Reduced power consumption can be achieved using optimal Sensor-Ports arrangement.
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For 1-Channel to 4-Channel, use 1 intra-port arrangement or use 2 inter-port arrangement (all SNS/SNSK pins should be on SAME Burst mask).
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For 5-Channel to 8-Channel, use 2 inter-port arrangement
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For 9-Channel to 12-Channel, use 1 intra-port and 1 inter-port arrangement.
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For 13-Channel to 16-Channel, use 2 inter-port arrangment. Sensor ports in inter-port arrangement When Wheels/Sliders are included in the design, consider the Special Needs for Wheel/Slider pins in the next page. In case of Routing considerations, Port-pin Alterative functionality requirements and good IO pin requirements additional Ports (limited to 4?) can be used. This will however result in additional memory consumption as a higher channel library will be used. Both Sensor-Port selection guidelines and Sensor-Pin guidelines need to be taken into consideration for Sensor Port-pin selection.