本文來源電子發燒友社區，作者：jf_25674040， 帖子地址：https://bbs.elecfans.com/jishu_2292606_1_1.html

一、安裝ubuntu22.04 server系統

1. 下載鏡像ubuntu-server-22.04-riscv64-visionfive-29042022

2. 在linux下使用etcher將鏡像寫入到SD卡；

   

3. 將SD卡插入到板卡SD卡卡槽中；

4. ssh 賬號: user 密碼:star5

二、修改dtb文件，并使能uart1

1. 獲取linux源代碼，并編譯源代碼linux源代碼

   sudo apt update

   sudo apt upgrade sudo apt install gcc-riscv64-linux-gnu git clone https://github.com/starfive-tech/linux.git cd linux make CROSS_COMPILE=riscv64-linux-gnu- ARCH=riscv visionfive_defconfig make CROSS_COMPILE=riscv64-linux-gnu- ARCH=riscv

2. 修改/linux/arch/riscv/boot/dts/starfive/jh7100-common.dtsi中與uart有關的接口

   

   

   

   sudo cp linux/arch/riscv/boot/dts/starfive/jh7100-starfive-visionfive-v1.dtb /boot/dtb-5.17.5-visionfive-foobar-29042022

   sudo sudo update-grub

   UART和DEV映射

   

三、硬件連接

四、軟件代碼

1. 串口類python代碼

import serial.tools.list_ports class MySerial(object): def init(self): self.ser = None

2. 工具類代碼

   class MyTools(object):

   def init(self): pass

   def bytes_to_strs(self, bytes_value): arry = ''.join(['%02x '% b for b in bytes_value]) return (arry.upper())

3. 甲醛類代碼：

   class ze08_ch20(object):

   def init(self) -> None: self.tools = MyTools() self.serial = MySerial() self.serial.open_serial_port('/dev/ttyS2', 9600) ''' self.recv_thread_ = threading.Thread(target=self.recv_thread) self.recv_thread_.start() ''' self.recv_thread()

   def calc_checksum(self, bytes_value): checksum = 0 for byte_ in bytes_value: checksum += byte_ checksum = checksum % (0xff + 1) if checksum == 0xff: return True return False

   def recv_thread(self): recv_buffer = bytes() #print("hello world") while True: try: recv_buffer += self.serial.read() except Exception as e: print(str(e)) if len(recv_buffer) < 9: time.sleep(0.01) #print(len(recv_buffer)) continue else: if recv_buffer[0] != 0xff: recv_buffer = recv_buffer[1:] else: if len(recv_buffer) >= 9: #print(len(recv_buffer)) phase_buffer = recv_buffer[:9] recv_buffer = recv_buffer[9:] print(self.tools.bytes_to_strs(phase_buffer)) if self.calc_checksum(phase_buffer) == True: int_formaldehyde = int.from_bytes(phase_buffer[4:6], byteorder='big') #print(int_formaldehyde) float_formaldehyde = int_formaldehyde /1000.0 *1.25 print(float_formaldehyde) time.sleep(0.001)

4. main代碼

   if __name__=="__main__":

   my_statistics = ze08_ch20()

   五、執行代碼獲取甲醛值