SN65HVD72DR Not Transmitting Properly? Here's Why

SN65HVD72DR Not Transmitting Properly? Here's Why and How to Fix It

If you're experiencing issues with the SN65HVD72DR not transmitting properly, there could be several reasons behind the fault. This device is a high-speed CAN transceiver , which is crucial for communication in automotive, industrial, and other embedded systems. Let's break down the common causes and step-by-step solutions to help you resolve the issue.

1. Power Supply Issues

Cause: The SN65HVD72DR requires a stable power supply for proper operation. Voltage fluctuations or insufficient power can lead to transmission issues.

Solution:

Check the power supply: Ensure that the supply voltage to the transceiver is within the specified range (typically 3.3V to 5V). Inspect for voltage dips: Use a multimeter or oscilloscope to confirm that the power remains stable during transmission. Replace or stabilize power supply if necessary.

2. Incorrect Configuration

Cause: Misconfiguring the device, such as incorrect termination or improper connection to the CAN bus, can prevent successful communication.

Solution:

Verify CAN Bus Termination: Ensure that termination resistors are correctly placed at the ends of the CAN bus. Typically, 120-ohm resistors should be at both ends of the bus. Check Pin Configuration: Review the datasheet for the correct pinout and connection settings. Ensure that the TX and RX pins are properly connected to your microcontroller or other CAN devices. Ensure Proper Bitrate Settings: The bitrate of the transceiver must match the rest of the network. Double-check the configuration and adjust the communication speed if needed.

3. Faulty or Loose Connections

Cause: Loose or poor-quality solder joints, or broken wires, can disrupt communication.

Solution:

Inspect all connections to the SN65HVD72DR. Look for broken wires, loose solder joints, or corroded connections. Resolder any suspicious joints and ensure all pins are securely connected to the board. Replace damaged cables or connectors if required.

4. Signal Integrity Issues

Cause: Long cable lengths, improper routing, or interference from other electrical components can affect the signal integrity.

Solution:

Keep CAN Bus Wiring Short: Use twisted-pair cables for CAN bus communication to improve noise immunity and signal quality. Check for EMI (Electromagnetic Interference): Avoid running CAN cables parallel to high-power lines or noisy electronics. Use shielding where necessary. Use Proper Grounding Techniques to ensure a clean signal path.

5. Device or Network Overload

Cause: Too many nodes on the CAN bus or devices sending messages too quickly can overload the network, causing transmission errors.

Solution:

Reduce the number of devices on the CAN network if possible. Implement message filtering on the transmitting devices to limit traffic and reduce the load. Increase the network’s bitrate to allow faster communication between devices, but ensure all devices can handle the new speed.

6. Faulty SN65HVD72DR Chip

Cause: In some cases, the transceiver itself may be damaged or malfunctioning.

Solution:

Replace the SN65HVD72DR: If all other troubleshooting steps fail and the chip shows no signs of life, consider replacing the transceiver with a new one. Test with another known-good SN65HVD72DR: Swap out the chip to determine if the issue is isolated to the specific device.

Conclusion

To resolve issues with the SN65HVD72DR not transmitting properly, carefully follow these steps:

Check the power supply for stability. Verify configuration (termination, pinout, bitrate). Inspect connections and solder joints. Ensure signal integrity by improving wiring and shielding. Manage network load to prevent congestion. If all else fails, replace the faulty transceiver.

By systematically eliminating potential causes, you'll be able to restore proper functionality to the SN65HVD72DR and get your system back on track.