Motorola MPC533 Reference Manual page 797

MIOS14 Modulus Counter Submodule
From
Prescaler
or Pin
Clock
16-bit Up-Counter
Select
Figure 17-43. MIOS14 Example: Double Capture Period Measurement
17.13.3 MIOS14 Double Edge Single Output Pulse
Generation
Software can initialize the MIOS14 to generate both the rising and the falling edge of an
output pulse. With a MDASM, pulses as narrow as 50 ns can be generated since software
action is not needed between the edges. Pulses as long as 2.1 s can be generated. When an
interrupt is desired, it can be selected to occur on every edge or only after the second edge.
Figure 17-44 shows how a counter submodule and a MDASM can be used to generate both
edges of a single output pulse. The software puts the compare value for one edge in register
A and the other one in register B2. The MDASM automatically creates both edges and the
pulse can be selected by software to be a high-going or a low-going. After the trailing edge,
the MDASM stops to await further commands from the software. Note that a single edge
output can be generated by writing to only one register.
MOTOROLA Chapter 17. Modular Input/Output Subsystem (MIOS14)
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
MIOS14 Double Action Submodule
in IPM mode (MOD3-MOD0 = 0b0010)
Bus
Select
16-bit Register A
Two
16-bit
Counter
16-bit Register B1
Buses
16-bit Register B2
Submodule Bus
MIOS14 Function Examples
Input
Signal
Edge
Detect
Input
Capture
Interrupt
on
Designated
Edge
17-73