MPC555CME Freescale Semiconductor, MPC555CME Datasheet - Page 576

• Manufacturer Part Number: MPC555CME
• Description: KIT EVALUATION FOR MPC555
• Manufacturer: Freescale Semiconductor
• Type: Microcontrollerr

Specifications of MPC555CME

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Processor To Be Evaluated: MPC555
• Data Bus Width: 32 bit
• Interface Type: RS-232
• For Use With/related Products: MPC555
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

15.15.2 MIOS1 Input Double Edge Period Measurement
MPC555
USER’S MANUAL
Prescaler
MIOS Modulus Counter Submodule
Select
Clock
Two samples are available to the software from an MIOS double action submodule for
period measurement. The software can read the previous and the current edge sam-
ples and subtract them. As with pulse width measurement, the software can be sure
not to miss samples by ensuring that the interrupt response time is faster than the fast-
est input period. Alternately, when the software is just interested in the latest period
measurement, one 32-bit coherent read instruction can get both the current and the
previous samples. Depending on the prescaler divide ratio, period times can be mea-
sured from 50 ns to 6.7 s.
Figure 15-10
of period measurement. The software designates whether the rising or falling edge of
the input signal is to be used for the measurements. When the edge is detected, the
state of the 16-bit counter bus is stored in register A and the content of register B1 is
transferred to register B2. After register B2 is safely latched, the content of register A
is transferred to register B1. This procedure gives the software coherent current and
previous samples in registers A and B2 at all times. An interrupt is available for the cas-
es where the software needs to be aware of each new sample. Note that a software
option is provided to also generate an interrupt after the first edge.
or Pin
From
Figure 15-10 MIOS1 Example: Double Capture Period Measurement
/
MPC556
16-bit Up-Counter
shows a counter submodule and a DASM combination as an example
MODULAR INPUT/OUTPUT SUBSYSTEM (MIOS1)
Submodule Bus
Rev. 15 October 2000
Counter
Buses
16-bit
Two
Select
Bus
in IPM mode (MOD3-MOD0 = 0b0010)
16-bit Register B1
16-bit Register B2
16-bit Register A
MIOS Double Action Submodule
Designated
Interrupt
Capture
Detect
Edge
Input
Edge
on
Input
MOTOROLA
Pin
15-40