ADS1293 ECG Breakout Board with ESP32: DRDY Pin Stuck Low, No Data Output

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1

Hello everyone,
I am working on interfacing the ProtoCentral ADS1293 3-channel ECG breakout board with an ESP32-WROOM-32 module using SPI. I have been struggling with the DRDY pin, which remains stuck low (approx. 0.3V), and as a result, I’m not receiving any ECG data. The serial output shows continuous zeros, and the device repeatedly resets due to no DRDY signal.
Here are the important details of my setup and debugging:
• Wiring:
• ADS1293 VDD → 5V (confirmed stable)
• ADS1293 GND → ESP32 GND (shared)
• CS → GPIO5 (ESP32)
• SCLK → GPIO18 (ESP32)
• MOSI → GPIO23 (ESP32)
• MISO → GPIO19 (ESP32)
• DRDY → GPIO22 (ESP32, interrupt capable)
• RESET → GPIO2 (ESP32)
• Logic-level jumper on ADS1293 board set to 3.3V (for ESP32 compatibility)
• SPI Communication: Verified by reading register 0x03 correctly (returns 0x40), indicating SPI hardware is functional.
• Configuration Sequence:
• Power-up oscillator and analog front end with extended delays (1.5-3 seconds).
• Channel 2 configured with internal continuous test signal to avoid dependency on electrodes.
• Right Leg Drive enabled.
• Continuous conversion mode started.
• Observations:
All readback power and status registers show expected values (oscillator reg 0x05 = 0x04, AFE power 0x14 = 0x00, no error flags).
• DRDY pin is stuck LOW (0 V measured as ~0.3V), never toggling.
• Serial output shows zeros for ECG channels continuously.
• Code includes watchdog reset if no DRDY pulses within 5 seconds, triggering repeated resets.
• Troubleshooting already done:
• Confirmed power rails and common grounds.
• Verified wiring multiple times.
• Used internal test signals to isolate electrode wiring issues.
• Tried extended reset and power-up delays.
• Did NOT attempt writing the DRDY routing register (0x0F) since it is hardware routed on this board.
• Reduced SPI clock speed for stability.
My question:
Has anyone faced similar issues with DRDY stuck low on the ProtoCentral ADS1293 board with ESP32? Could this be a hardware defect, or am I missing a critical step in the initialization?
Any guidance on what additional checks I can do or how to force the chip into proper conversion mode would be greatly appreciated.
Thanks in advance!


ADS1293 ECG Breakout Board with ESP32: DRDY Pin Stuck Low, No Data Output
2

Please convert this into an annotated schematic so we can follow what you built without needing several reference sources. Be sure to show all connections, power, ground, power sources etc. Post links to technical information on the hardware items.

For your processor I found that there are several variants of the ESP32-WROOM-32 module, including the ESP32-WROOM-32D and ESP32-WROOM-32U, which differ in size and features. Each variant is designed to meet specific application needs while maintaining compatibility with the ESP32 family.

Posting the code would help others understand what you are doing.