Connecting external digital pin to MCU's pin.

[allegro]

I would like to connect a digital pin from a chip called CS5463
**broken link removed**
to my MCU.
The MCU input pin is defined as tristate.

My question is how can i be sure that the digital pin of the CS5463 will be able to change from '1' logic to '0' logic, meaning that it would be "strong" enough to change logic states?

What should i look for in each datasheet?

Thanks.

 

[blueroomelectronics]

Which microcontroller do you plan on connecting it to?

 

[allegro]

ADUC812, can you help me please?

 

[blueroomelectronics]

They both have SPI so as long as they're running from the same voltage they should be compatible.

 

[allegro]

But the two mentioned pins that i want to connect together, the CS5463 digital output pin and the MCU digital input pin are not SPI peripherals.
So is it stll ok?

 

[tresca]

Do they share the same power source(i.e the same ground connection) ? If so, then you can connect them together. Then 5V will be read as 5V.

If they do not share the same ground, 5V on the CS5463 maybe 12V on your MCU or any arbitary voltage that can damage your MCU.

 

[futz]

But the two mentioned pins that i want to connect together, the CS5463 digital output pin and the MCU digital input pin are not SPI peripherals.
So is it still ok?

As Bill says, as long as they're similar voltage it will probably be fine. Don't connect a 5V output to a 3.3V input pin though, unless the datasheet says it is 5V tolerant.

You can connect 3.3V outputs to 5V chip inputs though. I do it routinely. In a recent project I have my 3.3V ARM7 board outputting a servo pulse-train that I connect to an input pin on a 5V PIC 12F683. Works just fine.