MPC563XM Reference Manual, Rev. 1
834
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
Match1 (before TDL2) captures into Capture2 the timebase selected by TBS1, in order not to overwrite
the captured value of TDL1.
This mode is used for scheduling one timeout condition on two input signal transitions (pulse timeout).
23.4.5.4.4
Channel Modes on Output Signal Generation
Since channel logic can generate output signal transitions based on Matches, the channel can be viewed as
working in the following primary mode groups for signal generation:
•
Single Match: em_b_st, sm_st, sm_st_e, em_b_dt, sm_dt
•
Double Match: em_nb_st, bm_st, m2_st, m2_o_st, em_nb_dt, bm_dt, m2_dt, m2_o_dt
The channel logic supports various match channel modes with single/double match, as explained in the
following subsections.
Either Match, Blocking Modes (em_b_st, em_b_dt)
On an output signal these modes are useful when using two different time bases to set a required signal
transition. The first match condition which is met sets a required pin action, captures both time bases,
blocks any effects of the other recognition, and generates a service request. Because the first match
recognition blocks the other, the microcode can get good separation in the function entry table as to which
match caused the timeout first, and both time bases are captured, enabling the microcode to compare one
timebase to the other at the moment of the match recognition. These modes can be used for:
•
Scheduling a required pin action to the first match recognition of two different time bases.
•
Cancelling a programmed pin action scheduled on one time base by match on another timebase (as
a consequence of
). Microcode has to set the OPAC register of the cancelling match to
no-action and the OPAC register of the other match to the required pin action which may be
blocked. If Match1 is the cancelling match, it blocks the pin action also in case of two matches at
the same time, since it has priority in this case. If match2 is the cancelling match, it does not block
the pin action in case of two matches at the same time.
Either Match, Non Blocking Modes (em_nb_st, em_nb_dt)
On an output signal these modes are useful in combination with the ME bit set on the entry point, to define
an interlaced operation. For example, each match recognition can set a pin action, and the second pin
action is not sensitive to microcode latency (ME bit asserted). Example for usage is PWM interlaced
function on which the latency is determined by the period and not the duty cycle.
Another possibility is using one match for pin actions and the other match for an unrelated timed task
without pin action (double the functionality of a single channel).
Match2 Request Modes (m2_st, m2_dt)
On an output signal, these modes can generate narrow pulses or do conditional pin actions. A conditional
pin action means that the pin state is changed only if the match recognitions occurred in the correct order,
since the match2 recognition which generates the service request also has priority over the pin action and
blocks future match1 recognitions.