Help understanding I2C code for the MPU6050

Projects Networking, Protocols, and Devices
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Datasheet for MPU-6050: MPU-6050 | TDK

Code snippet:

Wire.beginTransmission(0x68);
Wire.write(0x3B); // starting with register 0x3B (ACCEL_XOUT_H)
Wire.endTransmission(false);
Wire.requestFrom(0x68,14,true); // request a total of 14 registers
AcX=Wire.read()<<8|Wire.read(); // 0x3B (ACCEL_XOUT_H) & 0x3C (ACCEL_XOUT_L)
AcY=Wire.read()<<8|Wire.read(); // 0x3D (ACCEL_YOUT_H) & 0x3E (ACCEL_YOUT_L)
AcZ=Wire.read()<<8|Wire.read(); // 0x3F (ACCEL_ZOUT_H) & 0x40 (ACCEL_ZOUT_L)

Does writing the address of the information we want to read (line 2) allow the requestFrom call to know which memory location to start reading from?

How do you know that the memory address 0x68 is the one to begin all communications on?

2

Does writing the address of the information we want to read (line 2) allow the requestFrom call to know which memory location to start reading from?

Yes!

How do you know that the memory slave address 0x68 is the one to begin all communications on?

0x68 (0b1101000) is the 7-bit I2C Bus address for the MPU6050 device which contains all those registers containing information. You first get access to the device by detecting its presence on the I2C bus through 'roll calling' and then you access to the internal registers.