User Guide
GD32450Z-EVAL
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display which mode be selected. The frequency of the output clock can be observed
through the oscilloscope by PA8 and PC9 pin.
Information via a serial port output as following:
5.19. CTC_Calibration
5.19.1. DEMO purpose
This demo includes the following functions of GD32 MCU:
Learn to use external low speed crystal oscillator (LXTAL) to implement the CTC
calibration function
Learn to use clock trim controller (CTC) to trim internal 48MHz RC oscillator
(IRC48M) clock
The CTC unit trim the frequency of the IRC48M based on an external accurate reference
signal source. It can automatically adjust the trim value to provide a precise IRC48M
clock.
5.19.2. DEMO running result
Download the program <19_CTC_Calibration > to the GD32450Z-EVAL-V1.1 board and
run. The LED1 will turn on if the internal 48MHz RC oscillator (IRC48M) clock trim is OK.
5.20. PMU_sleep_wakeup
5.20.1. DEMO purpose
This demo includes the following functions of GD32 MCU:
Learn to use the USART receive interrupt to wake up the PMU from sleep mode
5.20.2. DEMO running result
Download the program < 20_PMU_Sleep_Wakeup > to the EVAL board, jump the JP13
to USART with the jumper cap and connect serial cable to COM0. After power-on, all the
LEDs are off. The mcu will enter sleep mode and the software stop running. When the
USART0 receives a byte of data from the HyperTerminal, the mcu will wake up from a
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