Wire.write(regadd) // Queues WRITE bit > Register Address (PGA1) Wire.beginTransmission(address) // Queues START bit > 7-bit Slave Address (0x94)

Wire.begin() // intitalizes Ardiuno as a I2C device #include //Library that allows I2C communicationīyte address = 0x94 //confirmed with Purepath softwareīyte regadd = 0x01 // Register address for PGA1 Here is some short code I have written to read the gain value stored in the PGA1 register. I can update/read register values all day within the purepath software, but I cannot accomplish this using the Arduino. To accomplish this, I am using an Arduino UNO and the Wire library (simple I2C library). Serial.I am working on a project that requires me to read/update various register values of the PCM1865 via I2C. Size_t actually_read = Wire.readBytes(buf, 4) Serial.printf('Register value: %08lx ', _builtin_bswap32(buf)) įor an explanation on why we need _builtin_bswap32(), see How to print 32-bit uint32_t as eight hex digits in Arduino Option 2: Reading the register into an uint8_t array const uint8_t SLAVE_I2C_ADDRESS = 0b1010 Size_t actually_read = Wire.readBytes((uint8_t*)&buf, 4)

Wire.requestFrom(SLAVE_I2C_ADDRESS, 4) // This register is 32 bits = 4 bytes longĭelay(5) // Wait for data to be available

Wire.beginTransmission(SLAVE_I2C_ADDRESS) Option 1: Reading the register into an uint32_t (recommended) const uint8_t SLAVE_I2C_ADDRESS = 0b1010 Ĭonst uint16_t SLAVE_I2C_REGISTER_ADDRESS = 0x50 We will provide a full example with error handling in a followup post. This is a minimal example so it creates minimal confusion for the reader.

Additionally, we wait for data using delay() instead of Wire.available(). Note that this code does not implement error handling for the sake of simplicity. In my opinion, it’s most efficient to just try out the standard way of reading a register and start from there. Note that some devices like the LAN9303 have a slightly different addressing scheme or other peculiarities. It will work with almost all I2C devices like EEPROMs, ADCs and others, provided you have the correct. The following code demonstrates how to read a register that is 4 bytes (32 bits) long over I2C.

Wire library for arduino download