Three functions for a single pin?

Jim McBride

I'm using the MSP430F5342IRGZ and would like to view the DCO clock with an oscilloscope so I can verify that I set it up correctly. I want to use pin 13 which is designated as P1.0/TA0CLK/ACLK in the datasheet. I can route the DCO to ACLK using the clock registers. But I can't find anything in the user's guide to tell me how to set this pin's function to ACLK. The PSEL register only has two choices 0=GPIO and 1=alternate function (TA0CLK). How do I setup this pin for its third option, ACLK?

This is a specific question, but in general, on the MSP430's, how do you select the third function for those pins that have 3 functions?

over 12 years ago

0 OCY over 12 years ago

Expert 1620 points

That information is usually detailed in the PIN SCHEMATICS Section near the end of the respective Data-sheet.

0 Mikolaj Filar over 12 years ago in reply to OCY

Expert 1550 points

Hello Jim,

you can try to set P1DIR of this pin to '1'. (I haven't check that but it's the most logical solution :) ).

0 Jim McBride over 12 years ago in reply to Mikolaj Filar

Intellectual 260 points

Thanks for the quick responses.

There was nothing helpful inthe pin schematics in the datasheet, but Mikolaj's suggestion was correct. Set pin to alternate function P1SEL=1, and set direction to output P1DIR=1. I had already tried this unsuccessfully, but had made a cut-and-paste error and was setting the wrong pin to output! Thanks Mikolaj, your suggestion made me go back and check and find the issue.

0 Jens-Michael Gross over 12 years ago in reply to Jim McBride

Guru 227245 points

Jim McBride said:
There was nothing helpful inthe pin schematics in the datasheet

Indeed, the schematics only shows 'to module' and 'from module'. However, to and from are two different modules: to timer and from clock system. :)

The table below the schematics lists the logic table and connections.

0 Jim McBride over 12 years ago in reply to Jens-Michael Gross

Intellectual 260 points

Thanks Jens-Michael. I see the table below the pin schematics in the datasheet and it indeed shows exactly what I was looking for.

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Three functions for a single pin?