
MOTOROLA
Chapter 17. Modular Input/Output Subsystem (MIOS14)
17-3
MIOS14 Key Features
17.2 MIOS14 Key Features
The basic features of the MIOS14 are as follows:
Modular architecture at the silicon implementation level
Disable capability in each submodule to allow power saving when its function is not
needed
Six 16-bit counter buses to allow action submodules to use counter data
When not used for timing functions, every channel signal can be used as a port
signal: I/O, output only or input only, depending on the channel function.
Submodules’ signal status bits reflect the status of the signal
MIOS14 counter prescaler submodule (MCPSM):
— Centralized counter clock generator
— Programmable 4-bit modulus down-counter
— Wide range of possible division ratios: 2 through 16
— Count inhibit under software control
MIOS14 modulus counter submodule (MMCSM):
— Programmable 16-bit modulus up-counter with built-in programmable 8-bit
prescaler clocked by MCPSM output.
— Maximum increment frequency of the counter:
– Clocked by the internal MCPSM output: fSYS / 2
– Clocked by the external signal: fSYS / 4
— Flag setting and possible interrupt generation on overflow of the up-counter
— Time counter on internal clock with interrupt capability after a pre-determined
time
— Optional signal usable as an external event counter (pulse accumulator) with
overflow and interrupt capability after a pre-determined number of external
events.
— Usable as a regular free-running up-counter
— Capable of driving a dedicated 16-bit counter bus to provide timing information
to action submodules (the value driven is the contents of the 16-bit up-counter
register)
— Optional signal to externally force a load to the counter with modulus value
MIOS14 double action submodule (MDASM):
— Versatile 16-bit dual action unit allowing two events to occur before software
intervention is required
— Six software selectable modes allowing the MDASM to perform pulse width and
period measurements, PWM generation, single input capture and output
compare operations as well as port functions