FLY-EDDY Wiring
The FLY-EDDY connects to the toolhead board or mainboard via the I2C interface. The 5P cable assembly contains 4 I2C signal wires (VCC, GND, SDA, SCL) and 1 temperature detection wire (TEMP, onboard thermistor). Both models have identical signal definitions but are adapted for different platforms:
- EDDY-F (FPC cable): Specifically adapted for the EDDY interface on the SHT36 V3, SB2040 V3, and SB2040 PRO V3 toolhead boards
- EDDY-M (MX1.25 connector): Adapted for standard toolhead boards or mainboards, connected via the I2C interface. Specific I2C configuration must follow the actual mainboard definitions (see the I2C explanation below)
Cable Specifications
| Model | Cable | Specification |
|---|---|---|
| EDDY-M | Ribbon cable - single-ended MX1.25 | 5P (VCC / GND / SDA / SCL / TEMP), 30cm |
| EDDY-F | FPC cable | 5P (VCC / GND / SDA / SCL / TEMP), 0.5mm pitch, same-side contacts, optional 150mm / 200mm |
I2C Pinout
| Pin | Definition | Description |
|---|---|---|
| VCC | Power positive | 5V power supply |
| GND | Power ground | Common ground with MCU |
| SDA | I2C data line | Connect to the MCU's I2C SDA pin |
| SCL | I2C clock line | Connect to the MCU's I2C SCL pin |
| TEMP | Temperature detection | Onboard thermistor output, connect to the MCU's ADC pin for [temperature_probe] thermal drift compensation (optional) |
- EDDY-M: MX1.25 connector pinout (left to right) is SDA, TEMP, SCL, 5V, GND
- EDDY-F: The FPC cable is only compatible with the EDDY interface on FLY toolhead boards (SHT36 V3 / SB2040 V3 / SB2040 PRO V3); plug it in directly, no need to verify the pinout
SDA / SCL are open-drain signals. Do not connect capacitors (such as filter capacitors or decoupling capacitors), inductors, diodes, or other components in series or parallel on these signal lines. Do not route them through RC / LC filter circuits or external level shifters, as this will alter the signal rising edge timing and cause unstable I2C communication or errors.
The FLY-EDDY I2C address is fixed at 0x42 (42), corresponding to the configuration item i2c_address: 42.
Wiring Steps
Before starting the wiring, completely shut down the printer and disconnect the power supply. Do not plug or unplug cables, arrange the interface wiring, or touch the connectors while the power is on.
- EDDY-M (MX1.25 Connector)
- EDDY-F (FPC Cable)
- Insert the MX1.25 ribbon cable into the EDDY-M connector housing, matching the pinout order (left to right: SDA, TEMP, SCL, 5V, GND) one-to-one
- Connect the other end of the cable to the I2C interface on a standard toolhead board or mainboard, verifying the pin order against the silkscreen on the connector
- Connect the TEMP wire to an available ADC pin on the mainboard; if no ADC pin is available, it can be left unconnected, but the thermal drift compensation feature will be unavailable
- After firmly inserting the connector, gently pull the cable to ensure it does not come loose, and organize the routing to avoid dangling or pulling
When connecting the EDDY-M to a standard toolhead board or mainboard, i2c_mcu and i2c_bus must be filled in according to the actual mainboard's MCU definitions; when using software I2C, specify i2c_software_scl_pin / i2c_software_sda_pin. The I2C address is fixed at 0x42 (42), with a crystal frequency of 40MHz.
- Insert the FPC cable (5P, 0.5mm pitch, same-side contacts) into the EDDY-F connector: open the locking latch, insert the cable's gold fingers in the correct orientation, press flat, then close the latch to secure it
- Connect the other end of the cable to the EDDY interface on the SHT36 V3 / SB2040 V3 / SB2040 PRO V3 toolhead board; the FPC corresponds one-to-one with the toolhead board interface, so plug it in directly without needing to verify the pinout
- The TEMP wire is automatically connected to the temperature detection pin on the toolhead board's EDDY interface (e.g.,
gpio28on the SHT36 V3); no additional wiring is required - Ensure the cable is not bent, folded, or exposing copper foil, and avoid squeezing or damaging it during installation
SHT36 V3 toolhead board FPC connection diagram:
SB2040 V3 toolhead board FPC connection diagram:
Pin Comparison for Both Connection Methods
| Signal | EDDY-M (MX1.25 Connector) | EDDY-F (FPC Cable) | Toolhead Board / Mainboard Interface |
|---|---|---|---|
| Power positive | 5V | 5V | 5V / VCC |
| Power ground | GND | GND | GND |
| Data line | SDA | SDA | SDA |
| Clock line | SCL | SCL | SCL |
| Temperature detection | TEMP | TEMP | ADC pin (e.g., gpio28 on the SHT36 V3) |
The EDDY-M's MX1.25 connector pinout (left to right) is: SDA, TEMP, SCL, 5V, GND; the EDDY-F's FPC cable is only compatible with the FLY toolhead board EDDY interface, requiring no pinout verification.
Cable Routing Recommendations
- EDDY communication cables should be kept away from motor cables, heater cables, and heated bed cables to avoid I2C signal interference
- I2C cables should not be excessively long; poor cable quality or excessive routing length may cause unstable communication
- When routing must cross power cables, try to cross them perpendicularly
Post-Wiring Verification
After completing the wiring and confirming all connectors are firmly inserted, power on for verification:
- Perform drive current calibration:
LDC_CALIBRATE_DRIVE_CURRENT CHIP=fly_eddy_probe - Successful calibration completion indicates normal I2C communication; proceed with height calibration
- If I2C errors such as
BUS_TIMEOUTorInvalid read dataoccur, power off first to inspect the wiring, then refer to the I2C configuration items to adjust the bus speed
I2C Error Troubleshooting: EDDY Issue Collection
I2C Configuration Item Explanation: EDDY I2C Pin and Configuration Explanation