GODIYMODULES LINTTL3 TTL UART to LIN Bus Converter Data Analyzer Instruction Manual

1. Introduction

The GODIYMODULES LINTTL3 is a TTL UART to LIN bus converter module designed for communication monitoring and maintenance of LIN bus equipment. This module integrates the TJA1021 IC, providing a reliable interface between TTL UART and LIN bus protocols. It is suitable for various applications requiring LIN bus communication analysis and control.

2. Key Features

• Protocol Conversion: Facilitates seamless conversion between TTL UART and LIN bus protocols.
• Integrated IC: Utilizes the TJA1021 IC for robust performance.
• High Baud Rate: Supports a measured baud rate up to 57600bps, with a recommended maximum operating frequency of less than 20Kbps for optimal stability.
• Protection Features: Includes power supply anti-reverse connection protection and LIN bus anti-surge protection.
• Microcontroller Compatibility: Compatible with both 3.3V and 5V microcontroller systems.
• Application: Primarily used for communication monitoring and maintenance of LIN bus devices.

3. Setup and Connections

Before connecting the LINTTL3 module, ensure all power sources are disconnected. Refer to the pin descriptions and wiring diagrams for correct installation.

3.1 Pin Description

Image: Top view of the LINTTL3 module showing pin labels for VIN, INH, LIN, GND, RX, SLP, TX.

• VIN: Power supply positive pole (DC 12V/24V)
• INH: Used in host mode (refer to TJA1021 PDF for details)
• LIN: LIN BUS connection
• GND: Power supply negative pole
• TX: TTL serial port data output (Connects to RX of MCU)
• SLP: Sleep mode control
• RX: TTL serial port data input (Connects to TX of MCU)
• GND: Ground wire (Connects to MCU)

3.2 Wiring Diagram (Master-Slave Configuration)

Image: Example wiring diagram illustrating a master LINTTL3 module connected to multiple slave LINTTL3 modules on a LIN bus, powered by a 12V DC supply. This diagram shows the interconnection of VIN, GND, and LIN lines between modules and the master/slave microcontrollers.

When connecting the LINTTL3 module to a microcontroller (MCU), ensure the TX pin of the module connects to the RX pin of the MCU, and the RX pin of the module connects to the TX pin of the MCU. The GND pins should also be connected. For master-slave configurations, follow the provided wiring diagram carefully, paying attention to the power supply connections and LIN bus lines.

4. Operating Instructions

The LINTTL3 module acts as an interface between a microcontroller's UART and a LIN bus. It allows the microcontroller to send and receive data over the LIN network.

1. Power Supply: Connect a DC 12V or 24V power supply to the VIN and GND terminals of the module. Ensure correct polarity.
2. UART Connection: Connect the module's TX and RX pins to the corresponding RX and TX pins of your microcontroller (e.g., Arduino, Raspberry Pi). Connect the module's GND to the microcontroller's GND.
3. LIN Bus Connection: Connect the LIN pin of the module to the LIN bus line of your system.
4. Data Communication: Use your microcontroller's UART to send and receive data. The module will convert TTL UART signals to LIN bus signals and vice-versa.
5. Baud Rate: Configure your microcontroller's UART to communicate at the desired baud rate. The module supports up to 57600bps, but for LIN bus stability, a maximum operating frequency of less than 20Kbps is recommended.
6. Sleep Mode (SLP): The SLP pin can be used to control the module's sleep mode, reducing power consumption when the LIN bus is inactive. Refer to the TJA1021 datasheet for detailed control of this feature.

Important Note: When connecting the module to a computer's COM port directly, the computer can receive data. However, a standard computer COM port cannot act as a LIN bus host because it cannot generate the specific 13-bit start bit required by the LIN protocol. For host functionality, connect the module to a development board or microcontroller capable of generating the LIN protocol's start bit.

5. Specifications

6. Troubleshooting

• No Communication with Microcontroller:
  • Verify TX/RX connections are crossed (module TX to MCU RX, module RX to MCU TX).
  • Ensure common ground (GND) connection between the module and the microcontroller.
  • Check UART baud rate settings on the microcontroller match the expected rate.
• Issues with 3.3V Microcontrollers:

  While the module is stated to be compatible with 3.3V/5V systems, some users have reported that the onboard pull-up resistors are connected to a 5V supply derived from the 12V input. This can potentially stress 3.3V microcontrollers. If experiencing issues with 3.3V logic levels, consider the following:

  • Voltage Level Shifters: Use external voltage level shifters between the module's TTL UART pins and the 3.3V microcontroller.
  • Modify Onboard Regulator (Advanced Users Only): For advanced users, it may be possible to replace the onboard 5V regulator (e.g., 78L05) with a 3.3V regulator to ensure pull-ups operate at 3.3V. This modification should only be attempted by experienced individuals as it voids warranty and carries risk of damage.
• LIN Bus Communication Errors:
  • Ensure the LIN bus line is correctly connected and terminated if necessary (though LIN typically uses a single master and slaves with internal termination).
  • Verify the LIN bus voltage levels are within specification.
  • Check for proper master-slave configuration and addressing on the LIN network.

7. Maintenance

The LINTTL3 module is designed for reliable operation with minimal maintenance. Keep the module clean and free from dust and moisture. Avoid exposing it to extreme temperatures or mechanical stress. No user-serviceable parts are inside.

8. Warranty and Support

This product is manufactured by GODIYMODULES. For warranty information and technical support, please refer to the official GODIYMODULES website or contact their customer service directly. Keep your purchase receipt for warranty claims.