Introduction

Hello, everyone! I'm Chris, Field Application Engineer from Nuvoton Technology. Today, I will introduce you how to design NuMicro M251/ M252 application circuit. Let's start with the power application circuit of M251/M252. The external power should add 10uF and 0.1uF decoupling capacitors, and the capacitor should be placed close to the source of the external power supply. Before the external power enters the VDD/VDDIO/VBAT of the IC, 0.1uF bypass capacitors should be added separately, and the capacitors should be placed close to the IC. Before the external power enters the AVDD, the bead should be connected in series for filtering, and then 1uF, 0.1uF, and 0.01uF bypass capacitors should be added. The bead and capacitors should be placed close to the IC. Before connecting AVDD to VREF, first, connect the bead in series for filtering, and then add 2.2uF, 1uF, and 470pF bypass capacitors. The bead and capacitors should be placed close to the IC. A 1uF bypass capacitor should be added to the internal LDO power supply of the IC, and the capacitor should be placed close to the IC. AVSS and VSS should be connected in series with a bead for filtering. USB_VBUS should be connected in series with a 10-ohm resistor to enhance the ability of USB to resist EFT interference. USB_D+ and USB_D- should be connected in series with 27-ohm resistors for impedance matching. USB_VCC33_CAP needs to add a 1uF bypass capacitor. ICE_DAT and ICE_CLK should be connected to 100K ohm pull-up resistors. The two ends of the high-speed and low-speed crystal oscillators should be connected with an equivalent capacitance of 20pF to VSS. I2C_SCL and I2C_SDA should be connected to 4.7K ohm pull-up resistors. nRESET should be connected to a 10K ohm pull-up resistor and a 10 uF capacitor to VSS. The internal LDO power supply of the IC needs to add a 1 uF bypass capacitor, and the capacitor should be placed close to the IC. In addition, reference circuits for EBI, UART, SPI, and Audio are provided. VDD is connected to 4~32 MHz crystal oscillator, POR33, Power On Control, 5V to 1.5V LDO, IO Cell... and other circuits inside the IC. Among them, GPIO PF.4 to PF.6 and PA.0 to PA.5 output, the high level is equal to VDD. Vbus is connected to the USB 1.1 PHY inside the IC. This 1.5V regulator will provide 1.5V for Digital Logic, SRAM, Flash, POR15, LIRC, MIRC, HIRC... and so on. Vbat is connected to internal 1.5V RTC_LDO and provides 1.5V voltage for RTC, 32.768 kHz crystal oscillator, IO Cell PF.6. VDDIO is connected to some IO cell for use, and the output high level of PA.0 to PA.5 is equal to VDDIO. AVDD is connected to the analog circuit inside the IC, and VREF is the reference voltage of the analog circuit. That's all for the hardware design of the NuMicro M251/M252 series instruction. Thank you for watching it. If you have further questions, please contact us. #Tool #Training #Learning #Intermediate #en - For more information, please visit Nuvoton Technology Website: https://bit.ly/3hVdcmC Buy now: https://direct.nuvoton.com/numaker-m251sd Contact us: SalesSupport@nuvoton.com

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