9.7
Program Example for 12-bit PPG Timer
An example of 12-bit PPG timer programming is given below.
■
Program Example for 12-bit PPG Timer
● Processing specification
A remote control transmission frequency with a period of about 38 µs and a duty cycle of approx. 33%
•
is generated.
The compare value for the PPG output pulse cycle period giving the above period of about 38 µs at the
•
maximum gear speed with oscillation of 12.5 MHz (F
assumed to be 4 t
Compare value for cycle period (RCR23:SCL5 to SCL0 and RCR24:SCL11 to SCL6) = 38 µs/ (4 × 4/
10MHz) = 30
•
The compare value for the "H" width of the PPG output pulse giving the duty cycle of approx. 33% is
determined as below. At this time, the "H" width is about 3 µs.
Compare value for the "H" width (RCR21:HSC5 to HSC0 and RCR22:HSC11 to HSC6) =33/100 ×
Compare value for the cycle period = 0.33 × 30 = 10
● Coding example
RCR21 EQU
RCR22 EQU
RCR23 EQU
RCR24 EQU
;------------------------Main program---------------------------------------------------------------------------------
;---------------------------------------------------------------------------------------------------------------------
.
INST
0014H
0015H
0016H
0017H
CSEG
:
MOV
RCR21,#01001010B
MOV
RCR22,#00H
MOV
RCR23,#10011110B
MOV
RCR24,#00H
:
ENDS
END
CHAPTER 9 12-BIT PPG TIMER
) is determined as below. The count clock is
CH
; Address of 12-bit PPG control register 1
; Address of 12-bit PPG control register 2
; Address of 12-bit PPG control register 3
; Address of 12-bit PPG control register 4
; [CODE SEGMENT]
; Select count clock of 4 t
value for "H" width.
;
; Specify outputs enabled and counter operation start and
set the above compare value for cycle period.
;
and set the above compare
INST
223