[General] Interface between OR gate and PIC

[karthi06]

Recently i have purchased ACT series OR logic gate.My question is,could it interface with 5V microcontrollers ?

Thank you.

 

[wp100]

Hi,

The ACT range is said to have TTL Compatible levels so will directly interface with a 5v micro ports.

Is there any need to use an OR gate when two of the micro inputs pins can be programmed to act as an OR gate ?

 

[milan.rajik]

He is interfacing 2 crash (impact) sensors to PIC18F46K22. I told him to use one external interrupt pin to interface both sensors instead of using 2 ext int pins. That is why he is using 2 input OR gate between sensors outputs and MCUs INT0 pin.

 

[wp100]

He is interfacing 2 crash (impact) sensors to PIC18F46K22. I told him to use one external interrupt pin to interface both sensors instead of using 2 ext int pins. That is why he is using 2 input OR gate between sensors outputs and MCUs INT0 pin.

Hi,

Right, a shame he did not explain things fully.

Still, do wonder why he cannot use INT0 and 1 ?

Now looking back at his other post seems he has plenty of pins spare ? provided he moves is lcd connections to PortD

See little point in using an external crystal which would also free up 2 pins

 

[milan.rajik]

I told him to use only one ext int pin (INT0) so that INT1 and INT2 can be used for other purposes. Only one crash sensor is needed but he thinks if is better and safe to use 2 crash sensors in parallel so that if one of them fails then also his system will work. I told him to use OR gate to interface both sensors to INT0 pin.

 

[wp100]

I told him to use only one ext int pin (INT0) so that INT1 and INT2 can be used for other purposes. Only one crash sensor is needed but he thinks if is better and safe to use 2 crash sensors in parallel so that if one of them fails then also his system will work. I told him to use OR gate to interface both sensors to INT0 pin.

Hi,

Yes, can see your point about leaving spare interrupt pins.

Though if he wants to use 2 crash sensors, my choice would be to avoid using extra logic chips in the design when the micro has that ability; he seems to have plenty of spare pins and there is also the 4 pins Rb4-7 with the Interrupt on Change feature he can utilize.

 

[milan.rajik]

Hi

I told him to use the attached circuit and use INT0 on falling edge.