MC68376BAMFT20 Freescale Semiconductor, MC68376BAMFT20 Datasheet - Page 242

• Manufacturer Part Number: MC68376BAMFT20
• Manufacturer: Freescale Semiconductor

Specifications of MC68376BAMFT20

• Cpu Family: 68K/M683xx
• Device Core: ColdFire
• Device Core Size: 32b
• Frequency (max): 20MHz
• Interface Type: QSPI/SCI
• Program Memory Type: ROM
• Program Memory Size: 8KB
• Total Internal Ram Size: 7.5KB
• # I/os (max): 18
• Number Of Timers - General Purpose: 2
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.25V
• Operating Supply Voltage (min): 4.75V
• On-chip Adc: 16-chx10-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 160
• Package Type: PQFP
• Lead Free Status / Rohs Status: Not Compliant

11.4.6 Period Measurement with Additional Transition Detect (PMA)
11.4.7 Period Measurement with Missing Transition Detect (PMM)
11.4.8 Position-Synchronized Pulse Generator (PSP)
11-8
MOTOROLA
This function and the following function are used primarily in toothed-wheel speed-
sensing applications, such as monitoring rotational speed of an engine. The period
measurement with additional transition detect function allows for a special-purpose
23-bit period measurement. It can detect the occurrence of an additional transition
(caused by an extra tooth on the sensed wheel) indicated by a period measurement
that is less than a programmable ratio of the previous period measurement.
Once detected, this condition can be counted and compared to a programmable num-
ber of additional transitions detected before TCR2 is reset to $FFFF. Alternatively, a
byte at an address specified by a channel parameter can be read and used as a flag.
A non-zero value of the flag indicates that TCR2 is to be reset to $FFFF once the next
additional transition is detected.
Refer to TPU programming note Period Measurement, Additional Transition Detect
(PMA) TPU Function (TPUPN15A/D) for more information.
Period measurement with missing transition detect allows a special-purpose 23-bit pe-
riod measurement. It detects the occurrence of a missing transition (caused by a miss-
ing tooth on the sensed wheel), indicated by a period measurement that is greater than
a programmable ratio of the previous period measurement. Once detected, this con-
dition can be counted and compared to a programmable number of additional transi-
tions detected before TCR2 is reset to $FFFF. In addition, one byte at an address
specified by a channel parameter can be read and used as a flag. A non-zero value of
the flag indicates that TCR2 is to be reset to $FFFF once the next missing transition
is detected.
Refer to TPU programming note Period Measurement, Missing Transition Detect
(PMM) TPU Function (TPUPN15B/D) for more information.
Any channel of the TPU can generate an output transition or pulse, which is a projec-
tion in time based on a reference period previously calculated on another channel.
Both TCRs are used in this algorithm: TCR1 is internally clocked, and TCR2 is clocked
by a position indicator in the user's device. An example of a TCR2 clock source is a
sensor that detects special teeth on the flywheel of an automobile using PMA or PMM.
The teeth are placed at known degrees of engine rotation; hence, TCR2 is a coarse
representation of engine degrees. For example, each count represents some number
of degrees.
Up to 15 position-synchronized pulse generator function channels can operate with a
single input reference channel executing a PMA or PMM input function. The input
channel measures and stores the time period between the flywheel teeth and resets
TCR2 when the engine reaches a reference position. The output channel uses the pe-
riod calculated by the input channel to project output transitions at specific engine de-
grees. Because the flywheel teeth might be 30 or more degrees apart, a fractional
TIME PROCESSOR UNIT
USER’S MANUAL
MC68336/376