Strange behaviour, I/O port, 68HC11

Hello,

This is probably becoming a legacy topic. I hope there's someone out there who can assist.

According to the 68HC11 reference manual, Port A PA3-6 can be general purpose outputs, or driven by timer output compare functions. If one disables the latter then it should simply be a matter of writing to the PA register, $1000 to set the pin voltage.

I find that that works fine for PA4-6, but despite many attempts I can't set PA3.

All the 'obvious' things have been tried. I've reread chapters 7 and 10 in the r.m., and AFAICT the registers are set correctly for gen purpose I/O - OC1M =TCTL1 = CFORC = 0. The pinout diagrams for E2 and E9 chip variants (I use E2) reference an input compare function for the PA3 pin. There's no reference to that elsewhere, it could be the problem but I don't know how to solve it if it is.

I need to use this pin as an output. Can anyone assist? TIA

Reply to
bruce varley
Loading thread data ...

Hi!

We need to know what specific device you are talking about. On a A8, for example, PA3 is an output. Whereas on the E-Controllers, PA3 is IO. You have to set DDRA3 in PACTL first, if you want that pin being an output. In addition to the reference manual you should look into the datasheet of your device.

Regards, Rene

Reply to
René König

Hi!

René König schrieb:

Now I read your posting carefully enough and saw, that you use an E2. So you have to set DDRA3 in PACTL.

Sorry for my first reply.

Regards, Rene

Reply to
René König

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.