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16-BIT TIMING OPERATIONS USING ST7262 OR ST7263B MCUs

& TIC2LR registers. These two registers act together as one 16-bit register that holds the

counter value to be stored in PulseEnd (PulseEndHR & PulseEndLR).

1.2.2.2 Example of input capture interrupt routine

.Input_Capt_Rt

Btjt TSR , #7 , Flag1

; Test Rising or falling edge ?

.Flag2

; Falling Edge

Ld

A , TSR

; Clear Interrupt Flag

Ld

A , TIC2HR

; Load TIC2R ( HR & LR ) into

Ld

PulseEndHR , A; PulseEnd ( HR & LR )

Ld

A , TIC2LR

;

Ld

PulseEndLR , A;

Iret

;

.Flag1

; Rising Edge

Ld

A , TSR

;Load TIC1R ( HR & LR ) into

Ld

A , TIC1HR

; PulseStart ( HR & LR )

Ld

PulseStartHR , A;

Ld

A , TIC1LR

;

Ld

PulseStartLR , A;

Iret

;

1.2.3 Frequency Measurement

1.2.3.1 Measurement principles

To measure frequency we will use the same technique we used for the ST7262 (see Section

1.1.3). We need only one input capture pin configured to detect rising edges and two 16-bit

variables to hold the 16-bit timer value at each input capture occurrence (StartPeriod) and

(EndPeriod). We will need also FirstEdge which indicates the first rising edge or the second

edge.