Hey Collin, Thanks and wish you and the rest of the team members a lovely thanksgiving. In the meantime I have more questions. 1. When the ADS is powered up from a single ended 5V supply (AVDD = +5V, AVSS = 0V), is it possible to use the ads in differential mode?? Like the positive input of channel 2 is connected to RA and the negative is connected to LA to measure ECG. 2. Could you please go through my schematics attached as pdf and tell me why my pcb is not working? (Please visit the site to view this file) 3. Regarding the SPI connection, I have powered up the ads from 3.3V (DVDD = 3.3V) and when I tried to communicate with a 3.3V microcontroller, I could not make it work. Instead, when I connect the ads with arduino uno with out logic shifter I could be able to read the registers and the test signals as attached in my previous question. The problem is using the oscilloscope, I found out there is about 1Vpp noise right the top of the clock and DRDY signal. Assuming that is the noise from the voltage difference between the 5V arduino spi and the 3.3ads spi lines, I tried to use voltage divider and fed the 3.3V to the ads side of the spi line. But the previous problem I have with the 3.3V microcontroller comes and I could not read the ads registers at all. If the AVDD is +5 Vand DVDD is 3.3V my assumption is the ads SPI line works at 3.3V. Am I wrong or is there something I missed here?? Thanks and looking forward to hear from you! Mes
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