PB0 - interrupt falling edge

[murielle]

Posted on July 08, 2003 at 09:06

PB0 - interrupt falling edge

[murielle]

Posted on July 02, 2003 at 14:33

I want to use port PB0 in entry interrupt falling edge.

Configuration :

PBDDR = 0xF6;

EICR = 0x80;

PBOR = 0x01;

PB0 is to 0

When I validate the interrupt PB0 (PBOR = 0x01), the interrupt occurs?!

The interrupt must occur on a falling edge and not on a low level.

How to solve my problem?

Thanks,

Murielle

[itsmejatinus]

Posted on July 03, 2003 at 09:23

What i have understood from your question is that you want to have the interrupt only when falling edge is detected .For this,you can set your interrupt sensitivity as falling edge only with IS1x bits as 00 and IPB bit as 1.

[murielle]

Posted on July 03, 2003 at 10:21

I try with PBOR = 0x00 (falling edge and low level) but it doesnt work.

What is IPB?

Best regards,

Murielle

[itsmejatinus]

Posted on July 03, 2003 at 11:50

The EICR register config. is like this -

IS11 IS10 IPB IS21 IS20 IPA TLIS TLIE

Make IS11 & IS10 as 00

& IPB as 1

so register value is 0x20.

[murielle]

Posted on July 03, 2003 at 12:02

I use a ST7FLITE0.

In the datasheet the EICR is like this :

IS31 IS30 IS21 IS20 IS11 IS10 IS01 IS00

There are 4 external interrupts.

Best regards,

Murielle

[itsmejatinus]

Posted on July 08, 2003 at 09:06

Ok.

For PortB interrupt the bits are IS31 and IS30. So to set the interrupt as falling edge only ...

Set the register value as 1000 0000 ===> 0x80

The value in this register is to be updated only when the interrupts are disabled.

[ This message was edited by: Ranjeet on 08-07-2003 14:00 ]