mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 312

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

14.3 TPU Operation
14.3.1 Event Timing
14.3.2 Channel Orthogonality
14.3.3 Interchannel Communication
14-4
MOTOROLA
All TPU2 functions are related to one of the two 16-bit time bases. Functions are syn-
thesized by combining sequences of match events and capture events. Because the
primitives are implemented in hardware, the TPU2 can determine precisely when a
match or capture event occurs, and respond rapidly. An event register for each
channel provides for simultaneity of match/capture event occurrences on all channels.
When a match or input capture event requiring service occurs, the affected channel
generates a service request to the scheduler. The scheduler determines the priority of
the request and assigns the channel to the microengine at the first available time. The
microengine performs the function defined by the content of the control store or emu-
lation RAM, using parameters from the parameter RAM.
Match and capture events are handled by independent channel hardware. This pro-
vides an event accuracy of one time-base clock period, regardless of the number of
channels that are active. An event normally causes a channel to request service. The
time needed to respond to and service an event is determined by which channels and
the number of channels requesting service, the relative priorities of the channels re-
questing service, and the microcode execution time of the active functions. Worst-
case event service time (latency) determines TPU2 performance in a given applica-
tion. Latency can be closely estimated. For more information, refer to the TPU
Reference Manual (TPURM/AD)
Most timer systems are limited by the fixed number of functions assigned to each pin.
All TPU2 channels contain identical hardware and are functionally equivalent in oper-
ation, so that any channel can be configured to perform any time function. Any function
can operate on the calling channel, and, under program control, on another channel
determined by the program or by a parameter. The user controls the combination of
time functions.
The autonomy of the TPU2 is enhanced by the ability of a channel to affect the oper-
ation of one or more other channels without CPU16 intervention. Interchannel commu-
nication can be accomplished by issuing a link service request to another channel, by
controlling another channel directly, or by accessing the parameter RAM of another
channel.
Freescale Semiconductor, Inc.
For More Information On This Product,
TIME PROCESSOR UNIT 2
Go to: www.freescale.com
MC68HC16Y3/916Y3
USER’S MANUAL