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16-BIT TIMING OPERATIONS USING ST7262 OR ST7263B MCUs

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 , ARTICR2

; 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 , ARTICR2

;Load The ART Inp Capt 2 register

Ld PulseEndLR , A

;Value into PulseEndLR

Ld A , ARTICCSR

;Clear The input capture interrupt

Iret

;Exit From Interrupt

1.1.2 Pulse Length measurement

1.1.2.1 Measurement Principles

As first example in this application note, we will try to measure the pulse length of an external

signal applied to the input capture pins.

Figure 3. Pulse Length Measurement

To perform this operation, two input captures are used together and they are configured as fol-

lows:

– Input capture1 pin (ARTIC1) configured to detect rising edges

– The input capture2 pin (ARTIC2) configured to detect falling edges

The ARTIC1 & ARTIC2 are connected together (Figure 4).

Two 16-bits variables are used to hold the 16-bits timer values on each valid input capture

edge (PulseStart for the rising edge and PulseEnd for the edge).The pulse length value can be

deduced later using a 16-bits substruction between PulseStart and PulseEnd

Pulse Length