Port 6 I/O configuration

mp_evolution · ‎2004-06-17

Posted on June 18, 2004 at 04:17

mp_evolution · ‎2011-05-17

Posted on May 17, 2011 at 11:36

I can't seem to get Port 6.1 to be configured properly as an Output Push-Pull TTL. I can see that the correct values have been set in the Emulator, but when the data pin is set to 1 it remains low and when you touch it with your finger it you can see it floating.

From what I can determine, it operates the same as when the port is configured as Output Open-Drain TTL.

This isn't a problem with port 1, it behaves as expected.

Is there some specific hardware problem on the ST9 with this port pin not being able to handle Out PP TTL?

Regards,

Mark Palmer

ritu · ‎2011-05-17

Posted on May 17, 2011 at 11:36

Hello,

In output mode you can configure any port pin eiher in pushpull or open drain mode and in input mode either in TTL or CMOS or shmitt trigger mode.

Normally when you configure any port pin in push pull o/p mode you should be able to drive the port pin with the level you put in corresponding data register ,whereas there is no guarantee of o/p level in open drain mode (Floating mode). And it holds true for P6.1 also.

If you are having some problem in driving P6.1 in push pull o/p mode, be sure to be of using a device which supports P6.1 in push-pull mode as in st92f163 devices P6.1 is a pure open drain pin so to drive the port weak pull up must be implemented externally.

Ritu