Part Number: ADS1299 Dear all, I'm building some EMG related projects with ADS1299 . It worked perfectly for a while, before I discovered that the data rate is abnormal and fluttering. I got lower than around 62 SPS (constantly changing and sometimes back to normal) instead of 250 SPS. After searching the forum, I found someone experiencing a very similar problem, but unfortunately the question is closed. The DRDY pin is switching at 62 SPS most of the time but sometimes it returns to 250 SPS briefly. I'm using internal 2.048Mhz clock source and enabled clock output. The clock signal is clean and stable. After some probing and checking, I found that when the problem occurs, I can not get proper test signal waveforms. It is always high. And when I stopped reading data with SPI transfers, some strange behavior is discovered on DRDY pin. It is randomly being pulled up for at least 4 data cycles. The register dump is as below 00: 3E 00111110 01: B6 10110110 02: D0 11010000 03: E0 11100000 04: 00 00000000 05: 65 01100101 06: 65 01100101 07: 65 01100101 08: 65 01100101 09: 65 01100101 0A: 65 01100101 0B: 65 01100101 0C: 65 01100101 0D: 00 00000000 0E: 00 00000000 0F: 00 00000000 10: 00 00000000 11: 00 00000000 12: 00 00000000 13: 00 00000000 14: 0F 00001111 15: 20 00100000 16: 00 00000000 17: 00 00000000 Any hint on this problem? Thanks. It seems that START pin is pulled high (with a high level of around 2.6V) and low randomly from time to time, which causes ADS1299 to restart. There is a 10k pulldown resistor between START pin and DGND and I use START command to start conversions. The START pin is not connected to anything else.
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