Freescale Semiconductor DRM079 manual KBISCKBACK, Kbisc, MTIMSCTOF, Mtimsc

Variable Speed DC Fan Control using the MC9RS08KA2, Rev. 0

Implementation

;X indicate the coil to be driven ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% SetPWM:

mov	#255, MTIMMOD		; OF period
mov	#(mMTIMSC_TRSTmMTIMSC_TOIE), MTIMSC; Reset and Start Timer
lda	#20		; Enable Interrupt & Edge only
mov	#(mKBISC_KBIE), KBISC
bset	KBISC_KBACK, KBISC		; Clear Flag
stx	PTAD		; Drive coil
TimingLoop:	MTIMSC_TOF, MTIMSC		; Clear TOF
bclr
wait	KBISC_KBF, KBISC, HallFound		; HALL sensor edge found
brset
dbnza	TimingLoop	; If no HALL output, Stop the driving
jmp	MotorHang
HallFound:	MTIMCNT, DriveTime
mov
cbeqa	#20, StableDrive
mov	#MaxDeadTime, DriveTime
StableDrive:	DeadTime
lda
add	DriveTime
sta	ActualPeriod		; Disconnect coil
clr	PTAD
mov	#(mKBISC_KBACK), KBISC		; Clear Flag and mask interrupt
mov	#(mMTIMSC_TSTPmMTIMSC_TRST), MTIMSC; mask interrupt and clear flag
rts

;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

;Read Temperature Sensor Value

;Timer prescalar=8 -> Timer clk~250kHz

;Bus = 2MHz

;Max OF period = 1.02ms

;Timer resolution = 4us ;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ReadSensor:

mov	#(MTIM_BUS_CLKMTIM_DIV_8), MTIMCLK; Change Timer resolution
mov	#63, MTIMMOD	; OF period
mov	#(mMTIMSC_TRSTmMTIMSC_TOIE), MTIMSC; Reset and Start Timer
mov	#(mACMPSC_ACMEmACMPSC_ACIEACMP_OUTPUT_RAISING), ACMPSC
bset	; Enable ACMP, start RC rise
	ACMPSC_ACF, ACMPSC	; Clear ACMP Flag
wait	; delay to OF and make the read process deterministic
brclr	ACMPSC_ACF, ACMPSC, NoReading
mov	MTIMCNT, SensorReading	; Clear ACMP Flag
bset	ACMPSC_ACF, ACMPSC
clr	ACMPSC	; disable ACMP
wait	#(mMTIMSC_TSTPmMTIMSC_TRST), MTIMSC; mask interrupt and clear flag
mov
mov	#(MTIM_BUS_CLKMTIM_DIV_256), MTIMCLK; Reset Timer resolution
rts

30 Freescale Semiconductor