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Sim Son
Sim Son
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I2C has a 7-bit address space. The device's actual address is 0b0111100 (=0x3c). The sequences 0b01111001 and 0b01111000 address the same slave while the first one (least significant bit is 1) starts a read transmission, the second one starts a write transmission.

Your display appearsThose least significant bits are nothing you need to only acknowledgecare about when using Wire.h: the beginmode of a write transmission, which means that itoperation is found. The reason why it doesn't acknowledgeautomatically set when addressed asusing 0b01111001Wire.startTransmission(addr) is simply because it does not support read operations(returns 0 when interfaced via I2Cslave ACK'ed write command) and Wire.requestFrom(addr) (returns 0 when slave ACK'ed read command).

I2C has a 7-bit address space. The device's actual address is 0b0111100 (=0x3c). The sequences 0b01111001 and 0b01111000 address the same slave while the first one (least significant bit is 1) starts a read transmission, the second one starts a write transmission.

Your display appears to only acknowledge the begin of a write transmission, which means that it is found. The reason why it doesn't acknowledge when addressed as 0b01111001 is simply because it does not support read operations when interfaced via I2C.

I2C has a 7-bit address space. The device's actual address is 0b0111100 (=0x3c). The sequences 0b01111001 and 0b01111000 address the same slave while the first one (least significant bit is 1) starts a read transmission, the second one starts a write transmission.

Those least significant bits are nothing you need to care about when using Wire.h: the mode of operation is automatically set when using Wire.startTransmission(addr) (returns 0 when slave ACK'ed write command) and Wire.requestFrom(addr) (returns 0 when slave ACK'ed read command).

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Sim Son
Sim Son
  • 1.9k
  • 14
  • 21

I2C has a 7-bit address space. The device's actual address is 0b0111100 (I2C has a 7-bit address space=0x3c). The sequences 0b01111001 and 0b01111000 address the same slave while the first one (least significant bit is 1) starts a read transmission, the second one starts a write transmission.

Your display appears to only acknowledge the begin of a write transmission, which means that it is found. The reason why it doesn't acknowledge when addressed as 0b01111001 is simply because it does not support read operations when interfaced via I2C.

The device's actual address is 0b0111100 (I2C has a 7-bit address space). The sequences 0b01111001 and 0b01111000 address the same slave while the first one (least significant bit is 1) starts a read transmission, the second one starts a write transmission.

Your display appears to only acknowledge the begin of a write transmission, which means that it is found. The reason why it doesn't acknowledge when addressed as 0b01111001 is simply because it does not support read operations when interfaced via I2C.

I2C has a 7-bit address space. The device's actual address is 0b0111100 (=0x3c). The sequences 0b01111001 and 0b01111000 address the same slave while the first one (least significant bit is 1) starts a read transmission, the second one starts a write transmission.

Your display appears to only acknowledge the begin of a write transmission, which means that it is found. The reason why it doesn't acknowledge when addressed as 0b01111001 is simply because it does not support read operations when interfaced via I2C.

Source Link
Sim Son
Sim Son
  • 1.9k
  • 14
  • 21

The device's actual address is 0b0111100 (I2C has a 7-bit address space). The sequences 0b01111001 and 0b01111000 address the same slave while the first one (least significant bit is 1) starts a read transmission, the second one starts a write transmission.

Your display appears to only acknowledge the begin of a write transmission, which means that it is found. The reason why it doesn't acknowledge when addressed as 0b01111001 is simply because it does not support read operations when interfaced via I2C.