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TMS320F28035PNT Fixing Bootloader Configuration Problems

TMS320F28035PNT Fixing Bootloader Configuration Problems: Analysis and Solutions

When working with the TMS320F28035PNT microcontroller, one common issue that developers may encounter is bootloader configuration problems. These problems can prevent the device from booting correctly or cause the bootloader to fail to function as expected. Below is a step-by-step guide to help identify and resolve these issues.

1. Identifying the Problem:

Bootloader configuration problems often manifest in the following ways:

The device doesn’t boot as expected, even after programming. The microcontroller doesn't start the application code from the correct Memory address. The bootloader mode is not properly entered after a reset. Bootloader fails to load or communicates with external flash or peripherals.

2. Common Causes of Bootloader Configuration Problems:

There are several possible reasons for bootloader issues on the TMS320F28035PNT:

Incorrect Bootloader Configuration Settings: The microcontroller has specific configuration registers that determine the boot process (e.g., boot from flash, UART, or I2C). If these are incorrectly set, the microcontroller may not enter bootloader mode properly.

Incorrect Memory Allocation: The memory map could be incorrectly configured, meaning the bootloader might not know where the application code is located in flash memory.

Boot Pin Configuration: The TMS320F28035PNT uses specific pins (such as GPIO pins) to determine whether to enter bootloader mode. If these pins are misconfigured, the microcontroller might not boot into the correct mode.

Faulty Firmware/Bootloader Code: The bootloader code might be corrupted, incorrectly written, or incompatible with the current version of the hardware or toolchain.

3. Step-by-Step Troubleshooting and Solutions:

Step 1: Verify Boot Mode Configuration

Ensure that the TMS320F28035PNT is configured to boot from the correct source. The microcontroller supports different boot modes such as booting from flash, UART, or I2C. To check and fix this:

Check the boot configuration pins: Ensure the GPIO pins are set up properly for the desired boot mode. These pins usually need to be configured in the first few cycles after reset.

For example, GPIO pins like GPIO0, GPIO1, or GPIO2 are often used to select the boot mode.

Refer to the TMS320F28035PNT datasheet for the correct configuration of these pins.

Check the BOOT PIN settings in your configuration code: Make sure the settings match the desired boot source. Typically, the boot mode is selected by writing specific values to the boot-related registers.

Step 2: Verify the Memory Map

A bootloader configuration issue can occur if the memory allocation is incorrect. To resolve this:

Check the linker file to ensure the application code is placed in the correct memory segment. Check that the bootloader is not overwriting the application by occupying the same memory region. Make sure that the memory start and end addresses are correctly set to reflect the application code and bootloader regions in flash. Step 3: Validate Bootloader Firmware

If the bootloader code is corrupted or incompatible, it may fail to load the application. To resolve this:

Reprogram the bootloader: Rebuild the bootloader using the correct source code and re-flash it to the microcontroller. Check for updates to the bootloader that may address compatibility or bug issues with your current hardware. Step 4: Debug and Test Use the JTAG or Serial Debug Interface to check if the microcontroller enters bootloader mode properly after reset. Use breakpoints or debug messages in the bootloader code to ensure that it reaches the correct section of code and loads the application correctly. Step 5: Test with External Tools If the bootloader uses external peripherals (like UART or I2C), ensure the external devices are properly connected and configured. Use a serial terminal to monitor the bootloader’s communication with external memory or peripherals during boot-up. Step 6: Restore Defaults if Necessary

If all else fails, try restoring the microcontroller to its factory defaults and reprogramming the device with the correct bootloader configuration.

4. Conclusion:

Fixing bootloader configuration problems on the TMS320F28035PNT involves ensuring that the bootloader settings, memory map, boot configuration pins, and firmware are correctly set. By following the steps outlined above, you can systematically address the issue and get your device to boot correctly. Properly managing the bootloader and understanding the configuration process will help ensure smooth operation of your application code.