MC68HC11G5 Datasheet, PDF (138/195 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller

Freescale Semiconductor, Inc.
11.3.3.2
Compare Register 1A (ECMP1A)
This compare register holds the value of the PWM period which determines when interrupt 1
(EVENT1) occurs. On a successful comparison with EVCNT1, it generates EVENT1, clears
EVCNT1 and resets output EVO to zero (when EVPOL = 0).
11.3.3.3
Compare Register 1B (ECMP1B)
This compare register holds the duty value which determines when the output (EVO) is set to one
(when EVPOL = 0). The duty cycle can be expressed as a percentage of the period by the following
equation:
11.3.3.4
DUTY CYCLE = 100 x [1 - (ECMP1B)/(ECMP1A)] %
Counter 2 (EVCNT2)
EVCNT2 counts the number of pulses coming from the INPUT2 selector. It is cleared by a successful
comparison between itself and ECMP2A.
11.3.3.5
Compare Register 2A (ECMP2A)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before
EVCNT2 is cleared to zero.
11.3.3.6
Compare Register 2B (ECMP2B)
This compare register holds the number of the pulses to be accumulated by EVCNT2 before an
interrupt signal EVENT2 is generated. If enabled, EVENT2 will interrupt the CPU.
11.3.3.7
Input Unit 1 (EVI1)
This input unit selects the clock source for EVCNT1. If the input signal EVI1 (PH5) is used as a clock
source, this unit will select the rising edge, falling edge or both edges of the input signal. If the time-
base counter is used as a clock source, this unit will select the active gated input level which inhibits
counting while this input signal is at the active level.
11.3.3.8
Input Unit 2 (EVI2)
This input unit selects the clock source for EVCNT2. If the input signal EVI2 (PH4) is used as a clock
source, this unit will select the rising edge or falling edge of the input signal. If the time base counter
is used as a clock source, this unit will select the active gate input level which inhibits counting while
this input signal is at the active level. Even if the time-base counter has selected one of the eight
clock rates (E, E/2, E/4, E/8, E/16, E/32, E/64, or E/128), this input selector can select the E-clock
independently as its clock source.
11-8
EVENT COUNTER
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