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Renesas Electronics America - Knowledgebase

Will external interrupt be generated by detecting the level?

Latest Updated: 03/25/2017


With an external interrupt, can an interrupt be generated by detecting the level?


The V850E/MA1 features a low-level level detection function.[V850E/MA1]
In any other device, interrupts cannot be generated using the level.

However, a function that approximates the desired function can be implemented by reading the interrupt input signal state via a port.

To perform interrupt servicing with active level low:
(1)Set the port mode to input by setting the PM register.
(2)Set the falling edge for the detection edge.
When an edge-trigger interrupt is acknowledged:
(3)Perform the necessary processing by the interrupt.
(4)Before exiting the interrupt servicing, read the port to check the interrupt pin status.
(5)If the pin is at high level, quit exit the interrupt servicing.
(6)If the pin is being held at low level, set the corresponding interrupt request flag (to 1) and then exit the interrupt servicing.

Since the interrupt request flag is set in step (6), another interrupt can be acknowledged after recovering from this interrupt service.
This approach seems to approximate the desired level-triggered interrupt type of function.
[All V850 products except V850E/MA1]

Suitable Products
V850 Family