Cypress Perform

Home > Design Support > Cypress Developer CommunityTM > Cypress Forums > University Alliance > Analog Inputs Strangeness

Bookmark and Share
Cypress Developer CommunityTM
Forums | Videos | Blogs | Training | Rewards Program | Community Components



Analog Inputs Strangeness
Moderator:
PKX

Post Reply
Follow this topic



Analog Inputs Strangeness

mandrews281 posted on 06 Mar 2011 1:49 PM PST
Member
2 Forum Posts

I'm seeing something very strange with the analog inputs on J2/J3 on our Cypress IO board.  I have a potentiometer wired so that Pin 1 (VDDIO) is one one side of the pot and pin 14 (GND) is on the other side of the pot.  Pin2/P0_0/AI1 is connected to the potentiometer wiper.  When I move the wiper, AI1 is steady at about 50%, but _all_ the other analog inputs (AI2-AI8) follow the potentiometer.  When I attach the wiper to AI3, AI1-AI3 are steady and AI4-AI8 follow the wiper.  I've put a volt meter on the wiper and it's acting exactly as I'd expect.  I suspect I'm mis-wiring something; but what? 

What am I doing wrong?  I just noticed that digital 15/16 mention analog comparator for analog out.  Does it get used for analog in also?  If so, do I need to gound it

Here's some other anticipated answers: (1) I'm watching this in the driver station software not our software. (2) I'm setting the board up in enhanced IO mode.  (3) I flashed the board with the V2 hex file.  (4) I've borrowed a second board from a rookie team we are mentoring and saw the exact same behaviour on that board. (5) J1 and J4 are jumpered for 3.3V. (6) all 16 digital ports are configured for pulled down input.

Thanks in advance

Michael Andrews, FIRST Team 281




Re: Analog Inputs Strangeness

mandrews281 posted on 08 Mar 2011 06:35 PM PST
Member
2 Forum Posts

Found the problem.  I rechecked the wiring and the pot was connected to AI2.  AI3-AI8 are simply following AI2.

 

Thanks






ALL CONTENT AND MATERIALS ON THIS SITE ARE PROVIDED "AS IS". CYPRESS SEMICONDUCTOR AND ITS RESPECTIVE SUPPLIERS MAKE NO REPRESENTATIONS ABOUT THE SUITABILITY OF THESE MATERIALS FOR ANY PURPOSE AND DISCLAIM ALL WARRANTIES AND CONDITIONS WITH REGARD TO THESE MATERIALS, INCLUDING BUT NOT LIMITED TO, ALL IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT OF ANY THIRD PARTY INTELLECTUAL PROPERTY RIGHT. NO LICENSE, EITHER EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, IS GRANTED BY CYPRESS SEMICONDUCTOR. USE OF THE INFORMATION ON THIS SITE MAY REQUIRE A LICENSE FROM A THIRD PARTY, OR A LICENSE FROM CYPRESS SEMICONDUCTOR.

Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Terms and Conditions of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Terms and Conditions of this site. Cypress Semiconductor and its suppliers reserve the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.

Spec No: None; Sunset Owner: KXP; Secondary Owner: VWA; Sunset Date: 01/01/20