在上一篇文章 詳解 I2C的末尾，有這樣一張波形圖：

實(shí)例2

這個對應(yīng)的就是常見的從設(shè)備寄存器讀數(shù)據(jù)的波形，只是在寫數(shù)據(jù)時多了一個字節(jié)。

通用的從 I2C 設(shè)備讀寄存器數(shù)據(jù)的模式應(yīng)該是這樣的：

從從設(shè)備寄存器讀數(shù)據(jù)示例

在mpu6050 數(shù)據(jù)表 中的9.3 I2C Communications Protocol章節(jié)說明了 mpu6050 的 i2c 接口協(xié)議，符合通用模式。

mpu6050 單字節(jié)寫和加速寫序列如下：

mpu6050單字節(jié)寫和加速寫

mpu6050 單字節(jié)讀和加速讀序列如下：

mpu6050單字節(jié)讀和加速讀

上面的加速寫和加速讀都是以 2 個數(shù)據(jù)字節(jié)為例的。

從實(shí)例 2 的波形圖可以看出，啟動傳輸后，寫了0x12``0x13``0x143 個字節(jié)，這 3 個字節(jié)后都是NACK，然后是重復(fù)起始信號，跟著剛才地址字節(jié)0x12+1即0x13，I2C 從寫轉(zhuǎn)換到讀，然后開始讀數(shù)據(jù)字節(jié)。

對應(yīng)代碼為：

result = ch347_driver.i2c_set(device_index, 1)
if result:
    print("Success to set I2C speed.")
else:
    print("Failed to set I2C speed.")

result = ch347_driver.i2c_set_delay_ms(device_index, 1)
if result:
    print("Success to set I2C delay.")
else:
    print("Failed to set I2C delay.")


result = ch347_driver.stream_i2c(device_index, b'x12x13x14', 8)
if result:
    print("Success!")
else:
    print("Failed!")

將上面這段代碼稍加修改：

result = ch347_driver.i2c_set(device_index, 1)
if result:
    print("Success to set I2C speed.")
else:
    print("Failed to set I2C speed.")

result = ch347_driver.i2c_set_delay_ms(device_index, 1)
if result:
    print("Success to set I2C delay.")
else:
    print("Failed to set I2C delay.")


result = ch347_driver.stream_i2c(device_index, b'xd0x75', 1)
if result:
    print("Success! result:", result.hex())
else:
    print("Failed!")

mpu6050 模塊的地址是0b1101000(AD0 = 0)，左移 1 位得到設(shè)備寫地址0xd0，讀數(shù)據(jù)時的讀地址 ch347 會自動產(chǎn)生，波形如下：

讀寄存器0x75

還沒有連接 mpu6050 模塊，所以沒有數(shù)據(jù)返回。現(xiàn)在把 mpu6050 模塊 i2c 接口連接到 ch347 模塊上，運(yùn)行程序，結(jié)果為：

?  python test.py
Successfully opened device index: 0
Device Information:
iIndex: 0
DevicePath: ?USB#VID_1A86&PID_55DB&MI_02#7&2887B016&0&0002#{5446F048-98B4-4EF0-96E8-27994BAC0D00}
UsbClass: 0
FuncType: 1
DeviceID: USBVID_1A86&PID_55DB&MI_02#7&2887B016&0&0002#
ChipMode: 1
DevHandle: 912
BulkOutEndpMaxSize: 512
BulkInEndpMaxSize: 512
UsbSpeedType: 1
CH347IfNum: 0
DataUpEndp: 6
DataDnEndp: 6
ProductString:
ManufacturerString:
WriteTimeout: 500
ReadTimeout: 500
FuncDescStr: USB2.0 To SPI&IIC
FirewareVer: 64
 ch347.mDeviceInforS object at 0x000002465A1E63C0 >
Version Information:
Driver Version: 35
DLL Version: 34
Device Version: 64
Chip Type: 1
Success to set I2C speed.
Success to set I2C delay.
Success! result: 68
Successfully closed device index: 0

可以看到返回了數(shù)據(jù)0x68，0x75是'WHO_AM_I'寄存器，默認(rèn)值為0x68。

'WHO_AM_I'寄存器

完整代碼：

import ch347

dll_path = "ch347dlla64.dll"  # Replace with the actual path to the DLL
device_index = 0  # Set the device index according to your requirements

ch347_driver = ch347.CH347Driver(dll_path)

result = ch347_driver.open_device(device_index)
if result:
    print(f"Successfully opened device index: {device_index}")
else:
    print(f"Failed to close device index: {device_index}")

result, device_info = ch347_driver.get_device_info(device_index)
if result:
    print("Device Information:")
    print(f"iIndex: {device_info.iIndex}")
    print(f"DevicePath: {device_info.DevicePath.decode()}")
    print(f"UsbClass: {device_info.UsbClass}")
    print(f"FuncType: {device_info.FuncType}")
    print(f"DeviceID: {device_info.DeviceID.decode()}")
    print(f"ChipMode: {device_info.ChipMode}")
    print(f"DevHandle: {device_info.DevHandle}")
    print(f"BulkOutEndpMaxSize: {device_info.BulkOutEndpMaxSize}")
    print(f"BulkInEndpMaxSize: {device_info.BulkInEndpMaxSize}")
    print(f"UsbSpeedType: {device_info.UsbSpeedType}")
    print(f"CH347IfNum: {device_info.CH347IfNum}")
    print(f"DataUpEndp: {device_info.DataUpEndp}")
    print(f"DataDnEndp: {device_info.DataDnEndp}")
    print(f"ProductString: {device_info.ProductString.decode()}")
    print(f"ManufacturerString: {device_info.ManufacturerString.decode()}")
    print(f"WriteTimeout: {device_info.WriteTimeout}")
    print(f"ReadTimeout: {device_info.ReadTimeout}")
    print(f"FuncDescStr: {device_info.FuncDescStr.decode()}")
    print(f"FirewareVer: {device_info.FirewareVer}")
    print(repr(device_info))
else:
    print("Failed to get device information.")

result, driver_ver, dll_ver, device_ver, chip_type = ch347_driver.get_version(device_index)
if result:
    print("Version Information:")
    print(f"Driver Version: {driver_ver}")
    print(f"DLL Version: {dll_ver}")
    print(f"Device Version: {device_ver}")
    print(f"Chip Type: {chip_type}")
else:
    print("Failed to get version information.")

result = ch347_driver.i2c_set(device_index, 1)
if result:
    print("Success to set I2C speed.")
else:
    print("Failed to set I2C speed.")

result = ch347_driver.i2c_set_delay_ms(device_index, 1)
if result:
    print("Success to set I2C delay.")
else:
    print("Failed to set I2C delay.")


result = ch347_driver.stream_i2c(device_index, b'xd0x75', 1)
if result:
    print("Success! result:", result.hex())
else:
    print("Failed!")


# Example usage of CH347CloseDevice
result = ch347_driver.close_device(device_index)
if result:
    print(f"Successfully closed device index: {device_index}")
else:
    print(f"Failed to close device index: {device_index}")

接下來就可以對 mpu6050 各種功能進(jìn)行封裝，然后在電腦上直接獲取傳感器數(shù)據(jù)了。