[M480] Use External Signal as HXT Clock Source

[chhsieh3]

• Application: This sample code uses the external signal as the HXT clock source and is divided and output to the CLKO pin.
• BSP Version: M480 Series BSP CMSIS V3.04.000
• Hardware: NuMaker-PFM-M487 Ver 3.0

In this example program, the input square wave to XT1_IN (PF.3) is used as the clock source of HXT, and after frequency division, it is output to CLKO (PC.13) for use by other peripheral components to synchronize the frequency between different components. At this time, XT1_OUT can be used as GPIO.

To enable this function, the CFGXT1 (CONFIG0[27]) of the configuration register must be set.

You can use the KEIL development environment to make this setting. The process is Project → Options for Target → Utilities → Settings → Configure, and check Work as GPIO.

You can download the sample code at https://www.nuvoton.com/resource-downlo ... 1219135320