Op Amplifier

[shermantec]

Posted on August 26, 2003 at 15:37

Op Amplifier

[shermantec]

Posted on July 31, 2003 at 08:41

Hello

I want to use the Op-Amp as an Interrupt . I need halt the cpu and initiate a run mode on a predefined analog input threshold .

Is this feature possible with the ST7Flite0x family ?

Latino from Israel

[itsmejatinus]

Posted on August 14, 2003 at 14:11

The problem is not very clear to me. Could you please explain the requirement in detail ?

[ This message was edited by: Ranjeet on 18-08-2003 13:03 ]

[sjo]

Posted on August 15, 2003 at 12:42

I'm afraid this is not possible with the flite or any ST7.

The only devices with this sort of functionality are the 321/521 which feature an EVD pin as part of the Auxiliary Voltage detector(AVD), but this is a fixed threshold relative to the LVD settings intended for monitoring voltage rails.

Hope this helps

SJO

[sisto]

Posted on August 26, 2003 at 15:37

You may use an ei0 external interrupt port I/O pin connected to the digital output of a voltage comparator (instead of an operational amplifier) with an appropriate filtering and histeresis theresolds to avoid an unpredictable enter-exit from HALT mode due source voltage ripple .

For example use fall sense interrupt to enter in halt mode by HALT instruction and rise sense to exit from HALT mode.

That means: the interrupt handler routine should change the rise/fall sense of ext irq and handle a flag to monitor this toggle situation.

The flag may be avoided using the same or another input to read the digital level of voltage comparator output.

Is better to use a micropower RailToRail Comparator.

Sixtus