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## I need help about the ports of PSOC 4 BLE

Level 3
Level 3

Hello everyone,

I created a program in PSOC 4 BLE, but the opamp_1's analog port P2[2] and ADC's analog port P3[4] have a voltage of 3 V and i don't know why, someone can help to get solution about it? Just send the program for your PSOC 4 and test with a multimeter the ports P2[2] and P3[4] that you can see the voltage, don't need to create the circuit.

Follows the attachment of my program:

1 Solution

## Re: I need help about the ports of PSOC 4 BLE

Employee
Employee

What is the voltage of the RA and LA inputs?

The differential amplifier consisting of opamp_1 and opamp_2 amplifies the voltage difference of the RA and LA inputs.   If the difference is too big the output of opamps will be saturated.

The DC potential of the positive input of the opamp_4 is zero volt.  Any bias voltage is required at the input because the opamp_4 is used as a non-inverting amplifier.

I recommend to use a differential input of the ADC.  Please refer following code example and documents.

CE95272 - PSoC® 4 SAR ADC and Differential Amplifier

Regards,

Noriaki

3 Replies

## Re: I need help about the ports of PSOC 4 BLE

Employee
Employee

What is connected to the RA and LA inputs?

Regards,

Noriaki

## Re: I need help about the ports of PSOC 4 BLE

Level 3
Level 3

RA - Right Arm

LA - Left Arm

I'm trying to implement a eletrocardiogram

## Re: I need help about the ports of PSOC 4 BLE

Employee
Employee

What is the voltage of the RA and LA inputs?

The differential amplifier consisting of opamp_1 and opamp_2 amplifies the voltage difference of the RA and LA inputs.   If the difference is too big the output of opamps will be saturated.

The DC potential of the positive input of the opamp_4 is zero volt.  Any bias voltage is required at the input because the opamp_4 is used as a non-inverting amplifier.

I recommend to use a differential input of the ADC.  Please refer following code example and documents.

CE95272 - PSoC® 4 SAR ADC and Differential Amplifier

Regards,

Noriaki