Recovery Methods for RT595 and RT685 Development Boards When Programming Fails

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Recovery Methods for RT595 and RT685 Development Boards When Programming Fails

During the development and use of RT595 and RT685 development boards, developers often encounter a common issue reported by users: persistent errors during programming via a debugger, making it impossible to reprogram the board and effectively rendering it “bricked.” These issues can arise from various causes, such as incorrect FCB writing, interruptions during the download process, or other unknown anomalies.

This article introduces two effective recovery methods:

1. Using the SEC TOOL utility.
2. Using an external J-Link programmer.

Note: Both methods require setting the RT595 and RT685 boards to Serial ISP mode beforehand. NXP has released two RT685-based development boards (MIMXRT685-AUD-EVK and MIMXRT685-EVK) and one RT595 board. Since the RT595 board operates similarly to the RT685 boards, this article uses the MIMXRT685-AUD-EVK board for demonstration. Ensure the SDK version is correct during the process.

1. Preparation: Entering Serial ISP Mode

Using the MIMXRT685-AUD-EVK board as an example, set switches SW5[1-3] to “ON OFF OFF” to enter Serial ISP mode. This corresponds to the following pin levels:

• PIO1_17: High
• PIO1_16: High
• PIO1_15: Low

Refer to the RT600 User Manual for detailed mappings between ISP pins and boot modes.

2. Method 1: Recovery Using SEC TOOL 

1. Preparation: Generate APP Image

• Import SDK Demo: Open MCUXpresso IDE and import the demo project mimxrt685audevk_lpc_gpio_led_output_cm33.

• Modify Project Settings: Make two key configuration changes to ensure successful image generation.
• 
• Generate Hex File: After configuration, build the project to generate a Hex file for use with SEC TOOL.

2. Using SEC TOOL

• Download SEC TOOL: https://www.nxp.com/design/design-center/software/development-software/mcuxpresso-software-and-tools...
• Create Workspace: Launch SEC TOOL and create a new workspace for MIMXRT685S.
• Select Connection Method: RT500 and RT600 support USB, UART, SPI, and I2C. Choose one (e.g., UART via J5 or USB via J7). Only one protocol can be used at a time. If switching, power cycle the board.

• Configure Flash Type and Test: Select the default external NOR Flash for MIMXRT685-AUD-EVK, apply settings, and run a test.

• Build Image: Use the previously generated App image and click “Build Image.” 

 

• Program Image: Flash the image to the RT685 chip.

• Switch Boot Mode: Power off the board and set Boot mode to FlexSPI Boot from PortB:
  • PIO1_17: Low
  • PIO1_16: High
  • PIO1_15: Low
  • SW5[1-3]: “ON OFF ON”

Power on the board again. It should now operate normally and run the program successfully.

3. Method 2: Recovery Using J-Link Programmer

1. Preparation: Generate Flashable File

• Import the same demo project into MCUXpresso IDE and compile it without modifications to generate a Hex or S19 file.
• Download and install SEGGER J-Flash from SEGGER Official Website.

2. Hardware Setup

• Board Modifications:
  • Connect pins 2 and 3 of JP2.
  • Remove jumpers JP17, JP18, JP19 (ensure p3 is disconnected).
  • Set SW5 to “ON OFF OFF”.
• Device Connection:
  • Connect J-Link Plus to J19 on the board.
  • Connect J6 to the PC to power the board.

3. Programming with J-Flash

• Create New Project: Open J-Flash and create a new project for MIMXRT685S. Note: RT685 supports only SWD, not JTAG.

• Flash Program: Load the Hex file and flash it to the board.

 

• Switch Boot Mode: After flashing, power off the board and set Boot mode to FlexSPI Boot from PortB:
  • PIO1_17: Low
  • PIO1_16: High
  • PIO1_15: Low
  • SW5[1-3]: “ON OFF ON”

Power on the board again. It should now function normally and run the program successfully.

Conclusion

By following either of the two methods described above, developers can effectively recover RT595 and RT685 development boards from programming failures and restore normal operation. Choose the method that best suits your specific situation.