1e41f4b71Sopenharmony_ci# Magic Key 2e41f4b71Sopenharmony_ci 3e41f4b71Sopenharmony_ci 4e41f4b71Sopenharmony_ci## When to Use 5e41f4b71Sopenharmony_ci 6e41f4b71Sopenharmony_ciWhen the system does not respond, you can use the magic key to check whether the system is suspended by an interrupt lock or view the system task running status. 7e41f4b71Sopenharmony_ci 8e41f4b71Sopenharmony_ciIf interrupts are responded, you can use the magic key to check the task CPU percent (CPUP) and locate the task with the highest CPUP. Generally, the task with a higher priority preempts the CPU resources. 9e41f4b71Sopenharmony_ci 10e41f4b71Sopenharmony_ci 11e41f4b71Sopenharmony_ci## How to Configure 12e41f4b71Sopenharmony_ci 13e41f4b71Sopenharmony_ciThe magic key depends on the macro **LOSCFG_ENABLE_MAGICKEY**. 14e41f4b71Sopenharmony_ci 15e41f4b71Sopenharmony_ciTo configure **LOSCFG_ENABLE_MAGICKEY**: 16e41f4b71Sopenharmony_ci 17e41f4b71Sopenharmony_ci1. Run the **make menuconfig** command in **kernel/liteos_a**. 18e41f4b71Sopenharmony_ci2. Locate the **Debug** option and select **Enable MAGIC KEY**. 19e41f4b71Sopenharmony_ci 20e41f4b71Sopenharmony_ciThis option is selected by default. If it is not selected, the magic key is invalid. 21e41f4b71Sopenharmony_ci 22e41f4b71Sopenharmony_ci> **NOTE**<br> 23e41f4b71Sopenharmony_ci> On **menuconfig**, you can move the cursor to **LOSCFG_ENABLE_MAGICKEY** and enter a question mark (?) to view help information. 24e41f4b71Sopenharmony_ci 25e41f4b71Sopenharmony_ci## How to Use 26e41f4b71Sopenharmony_ci 27e41f4b71Sopenharmony_ci1. Press **Ctrl+R** to enable the magic key. 28e41f4b71Sopenharmony_ci 29e41f4b71Sopenharmony_ci When the UART or USB-to-virtual serial port is connected, press **Ctrl+R**. If "Magic key on" is displayed, the magic key is enabled. To disable it, press **Ctrl+R** again. If "Magic key off" is displayed, the magic key is disabled. 30e41f4b71Sopenharmony_ci 31e41f4b71Sopenharmony_ci The functions of the magic key are as follows: 32e41f4b71Sopenharmony_ci 33e41f4b71Sopenharmony_ci - **Ctrl+Z**: displays help information about the related magic keys. 34e41f4b71Sopenharmony_ci 35e41f4b71Sopenharmony_ci - **Ctrl+T**: displays task information. 36e41f4b71Sopenharmony_ci 37e41f4b71Sopenharmony_ci - **Ctrl+P**: allows the system to proactively enter the panic state. After the panic-related information is printed, the system is suspended. 38e41f4b71Sopenharmony_ci 39e41f4b71Sopenharmony_ci - **Ctrl+E**: Checks the integrity of the memory pool. If an error is detected, the system displays an error message. If no error is detected, the system displays "system memcheck over, all passed!". 40e41f4b71Sopenharmony_ci 41e41f4b71Sopenharmony_ci > **NOTE**<br> 42e41f4b71Sopenharmony_ci > If magic key is enabled, when special characters need to be entered through the UART or USB-to-virtual serial port, avoid using characters the same as the magic keys. Otherwise, the magic key may be triggered by mistake, causing errors in design. 43