68hc12

[carlosthejackle2001]

Can I connect the amplifier straight to the input of the 68hc12? If I do will it damage it or will it be fine?

The amplifier will be single rail of +5v

 

[Nigel Goodwin]

I suggest you add a series resistor to limit the current, just in case the pin should get set as an output!.

 

[carlosthejackle2001]

I suggest you add a series resistor to limit the current, just in case the pin should get set as an output!.

I think as soon as it's turned on it's an output before the code instructs the port to become an input... I think

Will a resistor of few KOhms be fine or should this current be measured and resistor judged accordingly? I don't have immediate access till midway through next week which is a pain

 

[akg]

[quote="carlosthejackle2001]I think as soon as it's turned on it's an output before the code instructs the port to become an input... I think

Will a resistor of few KOhms be fine or should this current be measured and resistor judged accordingly? I don't have immediate access till midway through next week which is a pain[/quote]

~1K will do.

 

[Nigel Goodwin]

I think as soon as it's turned on it's an output before the code instructs the port to become an input... I think

That would be rather a stupid design! - PIC's are inputs by default, and you have to set them to be an output. I can't imagine any manufacturer doing it the other way round?.

 

[akg]

That would be rather a stupid design! - PIC's are inputs by default, and you have to set them to be an output. I can't imagine any manufacturer doing it the other way round?.

hmm..in atmel 89 series (atleast in 89s52/89s8252) u have to write 1 to the port for it to become i/p, otherwise it is output by default afaik..