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issues configuring analog test pins for Analog compoent | Cypress Semiconductor

issues configuring analog test pins for Analog compoent

Summary: 10 Replies, Latest post by Bob Marlowe on 22 Sep 2016 12:54 PM PDT
Verified Answers: 0
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prabhu05fe_1711731's picture
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39 posts

Hello Everyone, 

 

I have been working on PSOC 3  for a while right now  my issue is 

providing an analog input (from the Electric counter machine) to the PSOC 3 pin (GPIO) and it is working fine with the proper function

but i would like to check the type of waveform present at the analog input pin using oscilloscope

so i connected one analog Test pin at the same gpio input pin of the PSOC 3

whereas the problem is whenever i connect the probe at the test pin PSOC  it is not functioning But  if i remove the probe from the test pin PSOC is functioning well

 

could anyone please tell me what could be the issue behind this problem i was not able to find the real cause of this problem any ideas or help would be really helpful for me

 

Thank you

prabhu

user_242978793's picture
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1365 posts

You are loading the circuit. You maybe introducing some unwanted signals.

prabhu05fe_1711731's picture
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39 posts

Thank you so much for you kind reply so how i can see the input analog signal(GPIO PSOC3) in oscilloscope is there is any other way to see the input signal in CRO? i

user_342122993's picture
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761 posts

Switch scope probe to x10 to increase input impedance / switch the probe ( can be bad probe).

user_1377889's picture
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10440 posts

The signal from your counter machine can be a switch that connects to GND. So when the contact is open, your input floats. That situation changes with the osc. probe: you are going to induce noise from power main into the floating pins.

 

Check the signal from your machine directly with a meter for open/closed signal. Use a pullup resistor (or configure the port accordingly)

 

Bob

prabhu05fe_1711731's picture
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39 posts

Thank you so much for your kind reply could you please verify my configuration i am using Analog pin and then  Drive mode kept as High impedance analog initial drive state Low(0)

Based on your suggestion can i set the drive mode to resistive pull up? or what else should i modify in my configuration?

 

user_1377889's picture
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10440 posts

I cannot recommend a pin configuration without knowing your signal source. Do you have a schematic of the output of your Electric counter machine? Is that signal really an analog signal?? Which voltage level???

 

Bob

prabhu05fe_1711731's picture
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39 posts

Thank you so much for your reply bob electric counter is a machine where we are using in our home to measure the consumption of power

AC signal 230V /50hz SIGNAL  and am taking input from the counter by using RJ45 cable and it is connected to the PSOC 3 GPIO pins (5V supply for GPIO) based on the Electric counter documentations it is indicating that it is demodulated signal 

you got any idea based on the above informations 

Thank you

prabhu

 

user_1377889's picture
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10440 posts

So your signal seems to be a digital signal and not an analog one? Can you provide a link to the counter's datasheet or description?

 

Bob

prabhu05fe_1711731's picture
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39 posts

Thank you so much for your kind reply am using counter ACE6000 

http://www.geiico.com.co/wp-content/uploads/2013/08/ACE6000-Technical-Br...

 

IT is counter machine where i connect the RJ45 cable and then it will be connected to PSOC3 GPIO pins 

i have found there is a common ground issue with the counter machine and the PCB ground 

whenever i connect the GND OF probe to the PCB GND there is a small electric spark getting genrerate on the PCB GND pin how can i resolve the common, GND issue is there is any other way can i able to see the waveforms?

Thank you

prabhu

user_1377889's picture
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10440 posts

There is no need to "see" the waveforms.

If you did not fry your PSoC3 yet, keep away from connecting a GPIO directly to the counter. The interface is RS232 which has +-12V level which is far more than the allowed 0 to 5V a GPIO will tolerate.

You will need a level shifter as a MAX232. When you have got a CY8CKIT-030 you should read about the serial interface and how to connect it correctly. That kit already has got a level shifter which you need to wire to your PSoC Rx and Tx pins.

 

Bob

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