19.7.4 Timer1 Gate Single-Pulse Mode
When Timer1 Gate Single-Pulse mode is enabled, it is possible to capture a single-pulse gate event. Timer1 Gate Single-Pulse mode is first enabled by setting the GSPM bit. Next, the GGO/DONE bit must be set. The Timer1 will be fully enabled on the next incrementing edge. On the next trailing edge of the pulse, the GGO/DONE bit will automatically be cleared. No other gate events will be allowed to increment Timer1 until the GGO/DONE bit is once again set in software.
Clearing the GSPM bit will also clear the GGO/DONE bit. See figure below for timing details.
Enabling the Toggle mode and the Single-Pulse mode simultaneously will permit both sections to work together. This allows the cycle times on the Timer1 gate source to be measured. See figure below for timing details.