SDCC 8051 programming....

[davorin]

read port c sdcc 8051

Sorry for maybe stupid question but never did any '51/52 programming before in C (o;


I see that ports can be directly read and writtn to just with a single statement like "P2_2 = 0" or "value = P0"...

So I do not need to setup input/output before accessing the pins..right?

 

[UroBoros]

sdcc 8051

Hai,
if you want to read PORT0,you can configure PORT0 as input by writing 0xFF into the port register first. If you want a port as output just watch the pull up status of the port. If no internal pullups,connect external pullups and write 0xFF you will get high on pins,write 0x00 you will pull down pins.
Picstudent

 

[XNOX_Rambo]

8051 manual sdcc programming

I can add that Port 0 is a little different from Ports 1-3.

If you write a 1 to any pin of Port 0, it will go into tri-state mode.
If you write a 1 to any pin of Ports 1-3, it will go high using a weak internal pull-up.
This pull-up is easily overdriven by external circuits.

So writing a 1 to any pin will both make it an input and output a weak
logic high state.

/Rambo

 

[SphinX]

Sorry for maybe stupid question but never did any '51/52 programming before in C (o;


I see that ports can be directly read and writtn to just with a single statement like "P2_2 = 0" or "value = P0"...

So I do not need to setup input/output before accessing the pins..right?

Simple answer "YES"

SphinX