ADS1296R - Hardware PACE detection problem - Spurious Pulse

Arun Kumar27

Other Parts Discussed in Thread: ADS1296R, CC2564, ADS1296

Hi,

I am working on ADS1296R with MSP430 to get ECG data.

I have followed PACE detection circuit from TI reference (by Tony Calabria).

After few trial and error with the resistor and capacitor values, I am able to detect a pulse of duration 0.1ms and above & 4mV and above.

1. Problem - When i see the GPIO pin on the CRO, i see a spurious pulse along with the PACE pulse from the simulator.

This pulse occurs even when the simulator is OFF. It occurs every 1.3 second.

2. Also, i would like to bring down the detection threshold voltage to 2mV (currently circuit can detect 4mV and above) as suggested in the document

Thanks

Arun

over 8 years ago

0 Brian Pisani over 8 years ago

TI__Mastermind 38745 points

Hey Arun,

1. That pulse may be something from your environment or the MSP430. I'm not aware of anything running that slow on either the ADS1296R or in Tony's pacemaker design.

2. Have you tried increasing the PGA gain in the ADS1296R?

Regards,
Brian Pisani

0 Arun Kumar27 over 8 years ago in reply to Brian Pisani

Intellectual 590 points

Hi Brian,

I did some more tests and it revealed the following.
In my custom board, i also have a CC2564 for transferring the data.
The spurious pulses are appearing whenever the BT is connected and data transmission is happening. When i disable the BT and just collect the data from ADS1296, it works perfect.

What might be causing this?

Thanks
Arun

0 Brian Pisani over 8 years ago in reply to Arun Kumar27

TI__Mastermind 38745 points

Hey Arun,

I am certain that it is EMI from the Bluetooth part.

-Brian

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ADS1296R - Hardware PACE detection problem - Spurious Pulse