SWCU191 February 2022 CC1311P3 , CC1311R3 , CC2651P3 , CC2651R3 , CC2651R3SIPA
The AUX COMPA peripheral is a high-performance continuous-time comparator that features:
For capacitive touch sensing, COMPA is used together with the ISRC and TDC peripherals. ISRC will then drive an internal reference voltage for COMPA, nominally 0.8 V, while charging the capacitance that is also connected to the COMPA input. The time from start of charging until the COMPA output goes high is measured using the TDC.
ISRC is not supported in all devices. Please consult the device datasheet.
Pulse counting is another application that involves COMPA and the TDC. In this application, the TDC prescaler counts COMPA events.
Figure 20-15 shows how COMPA connects to analog nodes and analog peripherals, as well as the digital interfaces. Proper reference DAC control and connections are described in Section 20.1.