External Reset Source (ERS)

An External Reset Source (ERS) is an external input to the timer module that can be used to trigger Start, Reset and Stop conditions for the timer. It can be selected by configuring the TUxyERS selection register and goes through edge/level detection and synchronization as shown in Figure 1. The polarity of the ERS signal is selected using the EPOL bit in the TUxyHLT register. Setting the EPOL bit will invert the state of the selected ERS source. Also included is a Continuous mode selection for Start/Stop conditions to provide an ERS-independent software controlled start/stop option. See the Start, Stop and Reset Events section for start, stop and Reset events.

  1. 1.Actions involving ERS require the ON bit to be set and a running clock.
  2. 2.The EPOL bit must not be changed when ON = 1. Changing EPOL will spontaneously cause an edge event and can cause timer output to flip.
Figure 1. ERS Edge/Level Detection, Synchronization and Polarity Control