When a timer needs to be updated – indicating that an interface or function is still alive and timeout should be delayed – there are two means of touching a timer:
- If the timer’s respective TIMERMGR_SETUP_j_k has
the appropriate value for its function, the timer can be set again by writing a
1 to the SET bit of the TIMERMGR_CONTROL_j_k register.
- As the timer should
remain enabled, this effectively means writing a 3 to the
TIMERMGR_CONTROL_j_k register for the timer to be touched
- If the timer’s respective TIMERMGR_SETUP_j_k
needs a new value, writing this value has the side effect of also setting the
timer – there is no need to also write to the SET bit of TIMERMGR_CONTROL_j_k.
This should be relatively infrequent during operation, as the setup values for
all timers must be written during initialization.
The preferred method for touching timers is using
the SET bit of TIMERMGR_CONTROL_j_k. It is considerably more efficient. The
reprogramming RAM is a single port RAM, and repeated writes to the
TIMERMGR_SETUP_j_k registers will impact overall timer performance and may result in
longer periods before a valid timeout is observed.