Fujitsu F202RA, MB89202 manual Program Example for 12-bit PPG Timer

CHAPTER 9 12-BIT PPG TIMER

9.7Program 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 ∝s 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 ∝s at the

maximum gear speed with oscillation of 12.5 MHz (FCH) is determined as below. The count clock is assumed to be 4 tINST.

Compare value for cycle period (RCR23:SCL5 to SCL0 and RCR24:SCL11 to SCL6) = 38 ∝s/ (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 ∝s.

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	0014H	; Address of 12-bit PPG control register 1
RCR22 EQU	0015H	; Address of 12-bit PPG control register 2
RCR23 EQU	0016H	; Address of 12-bit PPG control register 3
RCR24 EQU	0017H	; Address of 12-bit PPG control register 4
;------------------------	Main program---------------------------------------------------------------------------------
CSEG		; [CODE SEGMENT]
:
MOV	RCR21,#01001010B	; Select count clock of 4 tINST and set the above compare
		value for "H" width.
MOV	RCR22,#00H	;
MOV	RCR23,#10011110B	; Specify outputs enabled and counter operation start and
		set the above compare value for cycle period.
MOV	RCR24,#00H	;
:
ENDS
;---------------------------------------------------------------------------------------------------------------------
END

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