Modular Input/Output Subsystem (MIOS14)
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
17-19
17.8
MIOS14 Modulus Counter Submodule (MMCSM)
The MMCSM is a versatile counter submodule capable of performing complex counting and timing
functions, including modulus counting, in a wide range of applications. The MMCSM may also be
configured as an event counter, allowing the overflow flag to be set after a predefined number of events
(internal clocks or external events), or as a time source for other submodules.
NOTE
The MMCSM can also operate as a free running counter by loading the
modulus value of zero.
The main components of the MMCSM are an 8-bit prescaler counter, an 8-bit prescaler register, a 16-bit
up-counter register, a 16-bit modulus latch register, counter loading and interrupt flag generation logic.
The contents of the modulus latch register is transferred to the counter under the following three
conditions:
1. When an overflow occurs
2. When an appropriate transition occurs on the external load signal
3. When the program writes to the counter register. In this case, the value is first written into the
modulus register and immediately transferred to the counter.
Software can also write a value to the modulus register for later loading into the counter with one of the
two first criteria.
A software control register selects whether the clock input to the counter is one of the prescaler outputs or
the corresponding input signal. The polarity of the external input signal is also programmable.
The following sections describe the MMCSM in detail. A block diagram of the MMCSM is shown in
.
Summary of Contents for MPC561
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Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...