What should user do when there is no HXT (high speed crystal oscillator) connected to the system and user switches the s

[a_ziliu]

When the CPU is powered on, the high-speed internal oscillator (HIRC) is used as the clock source. After the Flash is stable, the Config value is read to switch to HXT. Therefore, during the period from power-on to Flash stabilization. The signal of the ICP Programming Tool can still be received for connection.

When the CPU clock source is set to HXT, and no clock source can be connected to the ICP Programming Tool, you can follow the steps below to connect to the ICP Programming Tool.

Connect the chip to the PC through the ICE interface;
Open the ICP Programming Tool on the PC; do not click Connection;
Maintain the reset pin of the chip at low logic / Press and hold Reset Pin on the Tiny Board
Click Connection on the ICP Programming Tool;
Connect the reset pin of the chip to the high logic / Release the Reset Pin on the Tiny Board;
Connect to the ICP Programming Tool.