FALSE INTERRUPT FOR HARDWARE PACE MAKER DETECTION-ADS1298

Likhitha Eugene James P

Expert 2270 points

Other Parts Discussed in Thread: ADS1298

Hi,

Foe the ecg acquisition we are using ads1298.

Our sampling frequency is 1000sps.

After turning on the pace buffer in PACE register we are getting false interrupt when we remove the patient leads.

We are oring the pace out 1 and pace out 2 to form the PMD.

If we turn off the pace buffer we are not able to see any interrupts.

we are not able to find the root cause of this issue.

Can you help us to resolve the issue.

Thanks,

Likhitha

over 9 years ago

0 Likhitha Eugene James P over 9 years ago

Expert 2270 points

We are not able to judge whether this issue is occuring because of hardware or some false software configuration.

0 Brian Pisani over 9 years ago

TI__Mastermind 38745 points

Hello Likhitha,

This is probably because the voltage at the inputs of the ADS1298 changes quickly when the inputs are removed from the patient. Are you using any form of lead-off detection?

Regards,
Brian

0 Likhitha Eugene James P over 9 years ago in reply to Brian Pisani

Expert 2270 points

Hi,
We are using dc leadoff detection .
LOFF=0x13;
LOFF_SENSP=0xFF;
LOFF_SENSN=0x02;
LOFF_FLIP=0x00;
Thanks,
Likhitha

0 Brian Pisani over 9 years ago in reply to Likhitha Eugene James P

TI__Mastermind 38745 points

Hey Likhitha,

Perhaps the channel is saturating when the electrodes are removed because of the lead-off detection pull-up resistor. To confirm this, try disabling lead-off detection for the channel you have connected to the pace amp and see if the issue persists. If it is we can discuss a workaround for your system.

Brian

0 Likhitha Eugene James P over 9 years ago in reply to Brian Pisani

Expert 2270 points

Hi Brian,

Thanks.
I will check and update you .

Thanks,
Likhitha

0 Likhitha Eugene James P over 9 years ago in reply to Likhitha Eugene James P

Expert 2270 points

Hi Brian,
I turned off the leadoff.My configuration is as follows:]
LOFF=0X00;
LOFF_SENSP=0X00;
LOFF_SENSN=0X00;
LOFF_FLIP=0X00;
CONFIG4=0X00;
After this configuration i was not able to observe false interrupts when i connect/disconnect the chest leads .
But the connect/disconnect of limb leads is causing false interrupt.
How can i avoid this?
Thanks,
Likhitha

0 Likhitha Eugene James P over 9 years ago in reply to Likhitha Eugene James P

Expert 2270 points

Hi Brian,
How can i avoid this issue?
Thanks,
Likhitha

0 Brian Pisani over 9 years ago in reply to Likhitha Eugene James P

TI__Mastermind 38745 points

Hey Likhitha,

What you could do is turn lead-off detection on again for all appropriate channels and then screen the ADS1298 output for the lead-off indicator in the channels that are multiplexed to the pace amplifiers. If the leads on the pace channels are off, then ignore the pacemaker interrupt in your software.

Regards,
Brian

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FALSE INTERRUPT FOR HARDWARE PACE MAKER DETECTION-ADS1298