8. Special I/O Functions

8.3.3Quadrature bi-pulse counter

Function

This function counts up or down the quadrature bi-pulse (2-phase pulses whose phases are shifted 90° each other). Counts up when phase A precedes, and counts down when phase B precedes. Both rising and falling edges of each phase are counted.

Consequently, 4 times count value against the pulse frequency is obtained.

Phase A

Phase B

Up count

Down count

When the count value reaches the comparison value 1 (or 2), the I/O interrupt program #1 (or #2) is activated (if the interrupt enable flag for each is ON).

This counter operation is enabled while the soft-gate is ON. The count value is reset to 0 when the soft-gate is changed from ON to OFF. The count value is also reset to 0 when the reset input comes ON.

When the soft-gate is OFF, the count value can be changed by writing the data into the comparison value 1 (or 2) register and setting the count preset flag 1 (or 2) to ON.

The comparison value 1 and 2 can be changed even when the soft-gate is ON. The count value range is -2147483648 to 2147483647 (32-bit data).

Hardware condition

Phase A and phase B (X000 and X001)

ON/OFF pulse width: 100 ms or more (max. 5 kHz)

Reset input (X002)

ON/OFF duration: 2 ms or more

Related registers

SW16: Function selection. Refer to section 8.1.

Function

Register/device

Remarks

Phase A

X000

 

Phase B

X001

 

Reset input

X002

 

Comparison value 1

SW19×SW18

Data range: -2147483648 to 2147483647

Comparison value 2

SW21×SW20

 

Count value

SW23×SW22

 

Soft-gate

S240

Operation is enabled when ON

Interrupt enable 1

S241

Interrupt 1 is enabled when ON

Count preset 1

S243

Used to preset the count value

Interrupt enable 2

S249

Interrupt 2 is enabled when ON

Count preset 2

S24B

Used to preset the count value

Basic Hardware and Function 277

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Toshiba 6F3B0250, PROSEC T1 T1S user manual Quadrature bi-pulse counter