SLAU443 Datasheet, PDF (17/68 Pages) Texas Instruments – EEG Front-End Performance Demonstration Kit

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ADS1299EEG-FE Daughter Card Hardware Introduction
4.6 Analog Inputs
The ADS1299EEG-FE is designed so that it can be used as a eight channel data acquisition board.
Arbitrary input signals can be fed to the ADS1299 by feeding the signal directly at connector J6. Figure 14
shows the input configurations that are available in the EVM.
Figure 14. Input Configurations Supported by the EEG-FE a) Differential Inputs b) Single ended inputs
4.6.1 Differential Inputs
To digitize eight differential inputs,
1. Set all jumpers to factory defaults as described in Section 2.5.
2. Remove jumpers from pin 7-36 of J6.
3. Provide the differential inputs on the even pins 8-36 of J6.
While used with differential inputs, care needs to be taken to ensure that the analog inputs are within the
input common mode range of the PGA. If the input differential signal is centered around 0V, the ADS1299
needs to be operated with a bipolar supply. Refer to Section 4.1 for details on setting the EVM to operate
with a bipolar supply.
4.6.2 Single Ended Inputs
For single ended inputs the measurement can be done with respect to the voltage applied to the SRB1 pin
of the ADS1299. To digitize eight single ended inputs,
1. Set all jumpers to factory defaults as described in
2. Remove jumpers from pin 7-36 of J6.
3. Short pin 5 and 6 of JP6. Set the SRB1 bit in the MISC1 register to route the SRB1 pin to the negative
input of the channels (refer to Section 8.3 for details). This will route BIAS_ELEC (mid supply) to the
negative inputs of the channels through the SRB1 pin.
4. Provide the Single ended inputs to pins 36, 32, 28, 24, 20, 16, 12, 8 of J6 for channels 1-8
respectively.
SLAU443 – May 2012
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