PIC16F15213 datasheet(142/439 Pages) MICROCHIP

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17.3

Individual Pin Configuration

A rising edge detector and a falling edge detector are present for each PORT pin. To enable a pin to detect a rising

edge, the associated bit of the IOCxP register must be set. To enable a pin to detect a falling edge, the associated bit

of the IOCxN register must be set. A PORT pin can be configured to detect rising and falling edges simultaneously by

setting both associated bits of the IOCxP and IOCxN registers, respectively.

17.4

Interrupt Flags

The bits located in the IOCxF registers are status flags that correspond to the interrupt-on-change pins of each port.

If an expected edge is detected on an appropriately enabled pin, then the status flag for that pin will be set, and

an interrupt will be generated if the IOCIE bit is set. The IOCIF bit located in the corresponding Peripheral Interrupt

Request (PIRx) register, is all the IOCxF bits ORd together. The IOCIF bit is read-only. All of the IOCxF Status bits

must be cleared to clear the IOCIF bit.

17.5

Clearing Interrupt Flags

The individual status flags (IOCxF register bits) will be cleared by resetting them to zero. If another edge is detected

during this clearing operation, the associated status flag will be set at the end of the sequence, regardless of the

value actually being written.

To ensure that no detected edge is lost while clearing flags, only AND operations masking out known changed bits

must be performed. The following sequence is an example of clearing an IOC interrupt flag using this method.

Example 17-1. Clearing Interrupt Flags (PORTA Example)

MOVLW

0xff

XORWF

IOCAF, W

ANDWF

IOCAF, F

17.6

Operation in Sleep

An interrupt-on-change event will wake the device from Sleep mode, if the IOCIE bit is set. If an edge is detected

while in Sleep mode, the IOCxF register will be updated prior to the first instruction executed out of Sleep.

17.7

PIC16F15213/14/23/24/43/44

IOC - Interrupt-on-Change

and its subsidiaries

Data Sheet

DS40002195E-page 142

PIC16F15213 Datasheet(PDF) 142 Page - Microchip Technology