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16-BIT TIMING OPERATIONS USING ST7262 OR ST7263B MCUs

Ld A , TBUCV

; Load the TBU counter value

Ld TmpTBU1 , A; into TmpTBU1

Ld A , ARTCAR

; Load the ART counter Value

Ld TmpART1 , A

; into TmpART1

Ld A , TBUCV

; Load the TBU counter value into

Ld TmpTBU2 , A; TmpTBU2

Ld A , TmpART1

; Compare ART & ICR

Cp A , IcapReg2

; If ART > ICR then Case 2

jrpl Case2

;

Ld A ,TmpTBU2; Case 1 : TBU = TBU2 - 1

Dec A

;

jra Next2

;

.Case2

Ld A , TmpTBU1

; Case TBU = TBU1

.Next2

Ld PulseEndHR , A; load TBUCV into PulseEndHR

Ld A , IcapReg2

; Load The ART Inp Capt 2 register

Ld PulseEndLR , A; Value into PulseEndLR

Iret

; Exit from Interrupt

.Flag1 Ld A , ARTICR1

; Latch the Input Cap Reg into

Ld IcapReg1 , A; IcapReg1

Ld A , ARTICCSR

; Clear Interrupt

Ld A , TBUCV

; Load the TBU counter value

Ld TmpTBU1 , A; into TmpTBU1

Ld A , ARTCAR

; Load the ART counter Value

Ld TmpART1 , A

; into TmpART1

Ld A , TBUCV

; Load the TBU counter value into

Ld TmpTBU2 , A; TmpTBU2

Ld A , TmpART1

; Compare ART & ICR

Cp A , IcapReg1

;

jrpl Case1

;

Ld A , TmpTBU2; Case : TBU = TBU2 - 1

Dec A

;

jra Next1

;

.Case1

Ld A , TmpTBU1

; Case TBU = TBU1

.Next1

Ld PulseStartHR , A; load TBUCV into PulseEndHR

Ld A , IcapReg1

; Load The ART Inp Capt 2 register

Ld PulseStartLR , A; Value into PulseEndLR

Iret

; Exit from Interrupt

1.1.3 Frequency Measurement

1.1.3.1 Measurement Principles

Frequency measurement is a little bit different from pulse length measurement. To get the fre-

quency, we measure the full signal period which can be defined by the time interval between

two consecutive rising edges (Figure 6)