TI中文支持网Part Number:AM2634
大家好：
我方目前使用AM263X-LP开发板，在测试外部Flash启动，我在烧录时将外部Flash全部擦除，未写入新的文件。重新上电后发现不能正常Debug，请问在这是什么原因？
我的引导模式选择为0101(QSPI (1S) – 单路读取 UART 回退模式)，开发板上电后串口会有如下信息显示：
Shine：
请看一下如果直接设置成uart boot模式，是否能进入uart boot模式？具体步骤可以看一下下面文档。https://software-dl.ti.com/mcu-plus-sdk/esd/AM263X/08_03_01_06/exports/docs/api_guide_am263x/TOOLS_BOOT.html#UART_BOOTLOADER_PYTHON_SCRIPT
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RL ?：
您好，设置成uart boot模式后(0111)，上电与QSPI (1S) – 单路读取 UART 回退模式(0101)现象一致，我将开发板设置为NOBOOT模式(0010)后，可正常烧录，请问此现象是否正常。
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Shine：
请问按照上面文档中的步骤配置后，串口有打印cccc吗？
Make sure the UART port used for terminal is identified as mentioned in Setup UART Terminal
Make sure you have the EVM power cable and UART cable connected as shown in Cable Connections
To boot applications using this script, POWER OFF the EVM
Switch to UART BOOT MODE.
POWER ON the EVM
To confirm that the board is in UART boot mode, open the UART terminal and confirm that you see the character 'C' getting printed on the console every 2-3 seconds.
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RL ?：
有的 大概3S一个C
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Shine：
我把您的问题升级到英文e2e论坛了，请关注下面帖子的回复。https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1136517/am2634-can-t-debug-after-erasing-qspi-flash
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Shine：
请看下面工程师的回复。
The AM263x-LP has default SBL NULL present on the flash. This secondary bootloader is loaded by ROM after identifying a valid x509 certificate. The SBL_NULL boots all the cores and executes WFI. This allows users to connects the debugger to any core and program an application via CCS.
As you have removed the SBL, the ROM is not able to recognize any valid x509 certificate, the cores are not correctly initialized. This is the reason, why you are not able to connect the debugger properly. This is also the reason you are seeing XMODEM prints from ROM with "C" because the X509 parsing has failed in QSPI and ROM could not boot any image hence it is waiting for a valid application via UART.
I suggest you to add a valid SBL (preferably SBL_NULL) if you intend to load the application via CCS.
