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Remove extra begin/endTransmission calls during reads
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Fixes jrowberg#670 and jrowberg#672
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@jrowberg
jrowberg committed Oct 14, 2022
1 parent 3b5e731 commit 98a3b4e
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Showing 2 changed files with 0 additions and 40 deletions.
19 changes: 0 additions & 19 deletions Arduino/I2Cdev/I2Cdev.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -234,18 +234,14 @@ int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8
useWire->beginTransmission(devAddr);
useWire->send(regAddr);
useWire->endTransmission();
useWire->beginTransmission(devAddr);
useWire->requestFrom((uint8_t)devAddr, (uint8_t)min((int)length - k, I2CDEVLIB_WIRE_BUFFER_LENGTH));

for (; useWire->available() && (timeout == 0 || millis() - t1 < timeout); count++) {
data[count] = useWire->receive();
#ifdef I2CDEV_SERIAL_DEBUG
Serial.print(data[count], HEX);
if (count + 1 < length) Serial.print(" ");
#endif
}

useWire->endTransmission();
}
#elif (ARDUINO == 100)
// Arduino v1.0.0, Wire library
Expand All @@ -258,18 +254,14 @@ int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8
useWire->beginTransmission(devAddr);
useWire->write(regAddr);
useWire->endTransmission();
useWire->beginTransmission(devAddr);
useWire->requestFrom((uint8_t)devAddr, (uint8_t)min((int)length - k, I2CDEVLIB_WIRE_BUFFER_LENGTH));

for (; useWire->available() && (timeout == 0 || millis() - t1 < timeout); count++) {
data[count] = useWire->read();
#ifdef I2CDEV_SERIAL_DEBUG
Serial.print(data[count], HEX);
if (count + 1 < length) Serial.print(" ");
#endif
}

useWire->endTransmission();
}
#elif (ARDUINO > 100)
// Arduino v1.0.1+, Wire library
Expand All @@ -282,9 +274,7 @@ int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8
useWire->beginTransmission(devAddr);
useWire->write(regAddr);
useWire->endTransmission();
useWire->beginTransmission(devAddr);
useWire->requestFrom((uint8_t)devAddr, (uint8_t)min((int)length - k, I2CDEVLIB_WIRE_BUFFER_LENGTH));

for (; useWire->available() && (timeout == 0 || millis() - t1 < timeout); count++) {
data[count] = useWire->read();
#ifdef I2CDEV_SERIAL_DEBUG
Expand Down Expand Up @@ -356,7 +346,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
useWire->beginTransmission(devAddr);
useWire->send(regAddr);
useWire->endTransmission();
useWire->beginTransmission(devAddr);
useWire->requestFrom(devAddr, (uint8_t)(length * 2)); // length=words, this wants bytes

bool msb = true; // starts with MSB, then LSB
Expand All @@ -375,8 +364,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
}
msb = !msb;
}

useWire->endTransmission();
}
#elif (ARDUINO == 100)
// Arduino v1.0.0, Wire library
Expand All @@ -389,7 +376,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
useWire->beginTransmission(devAddr);
useWire->write(regAddr);
useWire->endTransmission();
useWire->beginTransmission(devAddr);
useWire->requestFrom(devAddr, (uint8_t)(length * 2)); // length=words, this wants bytes

bool msb = true; // starts with MSB, then LSB
Expand All @@ -408,8 +394,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
}
msb = !msb;
}

useWire->endTransmission();
}
#elif (ARDUINO > 100)
// Arduino v1.0.1+, Wire library
Expand All @@ -422,7 +406,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
useWire->beginTransmission(devAddr);
useWire->write(regAddr);
useWire->endTransmission();
useWire->beginTransmission(devAddr);
useWire->requestFrom(devAddr, (uint8_t)(length * 2)); // length=words, this wants bytes

bool msb = true; // starts with MSB, then LSB
Expand All @@ -441,8 +424,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
}
msb = !msb;
}

useWire->endTransmission();
}
#endif

Expand Down
21 changes: 0 additions & 21 deletions MSP430/I2Cdev/I2Cdev.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -230,18 +230,14 @@ int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8
Wire.beginTransmission(devAddr);
Wire.send(regAddr);
Wire.endTransmission();
Wire.beginTransmission(devAddr);
Wire.requestFrom(devAddr, (uint8_t)min(length - k, I2CDEVLIB_WIRE_BUFFER_LENGTH));

for (; Wire.available() && (timeout == 0 || millis() - t1 < timeout); count++) {
data[count] = Wire.receive();
#ifdef I2CDEV_SERIAL_DEBUG
Serial.print(data[count], HEX);
if (count + 1 < length) Serial.print(" ");
#endif
}

Wire.endTransmission();
}
#elif (ARDUINO == 100)
// Arduino v1.0.0, Wire library
Expand All @@ -254,18 +250,14 @@ int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8
Wire.beginTransmission(devAddr);
Wire.write(regAddr);
Wire.endTransmission();
Wire.beginTransmission(devAddr);
Wire.requestFrom(devAddr, (uint8_t)min(length - k, I2CDEVLIB_WIRE_BUFFER_LENGTH));

for (; Wire.available() && (timeout == 0 || millis() - t1 < timeout); count++) {
data[count] = Wire.read();
#ifdef I2CDEV_SERIAL_DEBUG
Serial.print(data[count], HEX);
if (count + 1 < length) Serial.print(" ");
#endif
}

Wire.endTransmission();
}
#elif (ARDUINO > 100)
// Arduino v1.0.1+, Wire library
Expand All @@ -278,18 +270,14 @@ int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8
Wire.beginTransmission(devAddr);
Wire.write(regAddr);
Wire.endTransmission();
Wire.beginTransmission(devAddr);
Wire.requestFrom(devAddr, (uint8_t)min(length - k, I2CDEVLIB_WIRE_BUFFER_LENGTH));

for (; Wire.available() && (timeout == 0 || millis() - t1 < timeout); count++) {
data[count] = Wire.read();
#ifdef I2CDEV_SERIAL_DEBUG
Serial.print(data[count], HEX);
if (count + 1 < length) Serial.print(" ");
#endif
}

Wire.endTransmission();
}
#endif

Expand Down Expand Up @@ -357,7 +345,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
Wire.beginTransmission(devAddr);
Wire.send(regAddr);
Wire.endTransmission();
Wire.beginTransmission(devAddr);
Wire.requestFrom(devAddr, (uint8_t)(length * 2)); // length=words, this wants bytes

bool msb = true; // starts with MSB, then LSB
Expand All @@ -376,8 +363,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
}
msb = !msb;
}

Wire.endTransmission();
}
#elif (ARDUINO == 100)
// Arduino v1.0.0, Wire library
Expand All @@ -390,7 +375,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
Wire.beginTransmission(devAddr);
Wire.write(regAddr);
Wire.endTransmission();
Wire.beginTransmission(devAddr);
Wire.requestFrom(devAddr, (uint8_t)(length * 2)); // length=words, this wants bytes

bool msb = true; // starts with MSB, then LSB
Expand All @@ -409,8 +393,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
}
msb = !msb;
}

Wire.endTransmission();
}
#elif (ARDUINO > 100)
// Arduino v1.0.1+, Wire library
Expand All @@ -423,7 +405,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
Wire.beginTransmission(devAddr);
Wire.write(regAddr);
Wire.endTransmission();
Wire.beginTransmission(devAddr);
Wire.requestFrom(devAddr, (uint8_t)(length * 2)); // length=words, this wants bytes

bool msb = true; // starts with MSB, then LSB
Expand All @@ -442,8 +423,6 @@ int8_t I2Cdev::readWords(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint1
}
msb = !msb;
}

Wire.endTransmission();
}
#endif

Expand Down

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