Author Topic: LEGACY: 68HC11 DIO port problem  (Read 262 times)

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Offline AussieBruce

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LEGACY: 68HC11 DIO port problem
« on: June 16, 2021, 04:58:11 am »
I still use the old Motorola/Freescale 68HC11, and am having difficulty with PortA. According to the HC11 manual, PA-3,4,5 and 6 can double as GP outputs, and as outputs driven by the main timer output compare function. I believe I’ve done what’s needed to disconnect these pins from the timer (details below), and I can drive 4,5 and 6 OK, but not PA3, it appears to be Hi-Z rather than an output. There’s no reference to a DDR in the manual, and the diagrams of the port logic shows these pins as output only.

It doesn’t seems to be a hardware fault because more than one known good chip shows the problem.

The port setup I’ve done is to set register TCTL1 to zero, which should disconnect the timer. However, the documentation is a bit vague around this area and there are a number of references to other registers that may interact.

The device family is MC6811E2.

Can anyone assist?
 

Offline Benta

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Re: LEGACY: 68HC11 DIO port problem
« Reply #1 on: June 17, 2021, 09:10:11 pm »
That shouldn't be possible.
Are you sure your pinout is correct? PA7 can do this, but not PA3.

 
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