/*! LTC2655: Quad I2C 16-/12-Bit Rail-to-Rail DACs with 10ppm/C Max Reference @verbatim The LTC2655 is a family of Quad I2C 16-/12-Bit Rail-to-Rail DACs with integrated 10ppm/C max reference. The DACs have built-in high performance, rail-to-rail, output buffers and are guaranteed monotonic. The LTC2655-L has a full-scale output of 2.5V with the integrated reference and operates from a single 2.7V to 5.5V supply. The LTC2655-H has a full-scale output of 4.096V with the integrated reference and operates from a 4.5V to 5.5V supply. Each DAC can also operate with an external reference, which sets the full-scale output to 2 times the external reference voltage. The parts use the 2-wire I2C compatible serial interface. The LTC2655 operates in both the standard mode (maximum clock rate of 100kHz) and the fast mode (maximum clock rate of 400kHz). The LTC2655 incorporates a power-on reset circuit that is controlled by the PORSEL pin. If PORSEL is tied to GND the DACs power-on reset to zero-scale. If PORSEL is tied to VCC, the DACs power-on reset to mid-scale. I2C DATA FORMAT (MSB First): Byte #1 Byte #2 MSB LTC2655-16 : START SA6 SA5 SA4 SA3 SA2 SA1 SA0 W SACK C3 C2 C1 C0 A3 A2 A1 A0 SACK LTC2655-12 : START SA6 SA5 SA4 SA3 SA2 SA1 SA0 W SACK C3 C2 C1 C0 A3 A2 A1 A0 SACK Byte #3 Byte #4 LSB D15 D14 D13 D12 D11 D10 D9 D8 SACK D7 D6 D5 D4 D3 D2 D1 D0 SACK STOP D11 D10 D9 D8 D7 D6 D5 D4 SACK D3 D2 D1 D0 X X X X SACK STOP START: I2C Start SAx : I2C Address W : I2C Write (0) SACK : I2C Slave Generated Acknowledge (Active Low) Cx : DAC Command Code Ax : DAC Address (0=DACA, 1=DACB, 2=DACC, 3=DACD, 0xFF=All DACs) Dx : DAC Data Bits X : Don't care STOP : I2C Stop Example Code: Set DAC A to to 2V for 16-bit DAC. shift_count = 0; // 16-bit DAC does not have to be shifted dac_voltage = 2.0; // Sets dac voltage variable to 2v dac_code = LTC2655_voltage_to_code(dac_voltage, LTC2655_lsb, LTC2655_offset); // Calculate DAC code from voltage, lsb, and offset ack = LTC2655_write(LTC2655_I2C_ADDRESS, LTC2655_CMD_WRITE_UPDATE, LTC2655_DAC_A, dac_code); // Set DAC A with DAC code @endverbatim http://www.linear.com/product/LTC2655 http://www.linear.com/product/LTC2655#demoboards Copyright 2018(c) Analog Devices, Inc. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of Analog Devices, Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. - The use of this software may or may not infringe the patent rights of one or more patent holders. This license does not release you from the requirement that you obtain separate licenses from these patent holders to use this software. - Use of the software either in source or binary form, must be run on or directly connected to an Analog Devices Inc. component. THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /*! @file @ingroup LTC2655 Header for LTC2655: Quad I2C 16-/12-Bit Rail-to-Rail DACs with 10ppm/C Max Reference */ #ifndef LTC2655_H #define LTC2655_H #include //! @name I2C_Addresses //!@{ // I2C Address Choices: // To choose an address, comment out all options except the // configuration on the demo board. // Address assignment // LTC2655 I2C Address // AD2 AD1 AD0 #define LTC2655_I2C_ADDRESS 0x10 // GND GND GND // #define LTC2655_I2C_ADDRESS 0x11 // GND GND Float // #define LTC2655_I2C_ADDRESS 0x12 // GND GND Vcc // #define LTC2655_I2C_ADDRESS 0x13 // GND Float GND // #define LTC2655_I2C_ADDRESS 0x20 // GND Float Float // #define LTC2655_I2C_ADDRESS 0x21 // GND Float Vcc // #define LTC2655_I2C_ADDRESS 0x22 // GND Vcc GND // #define LTC2655_I2C_ADDRESS 0x23 // GND Vcc Float // #define LTC2655_I2C_ADDRESS 0x30 // GND Vcc Vcc // #define LTC2655_I2C_ADDRESS 0x31 // Float GND GND // #define LTC2655_I2C_ADDRESS 0x32 // Float GND Float // #define LTC2655_I2C_ADDRESS 0x33 // Float GND Vcc // #define LTC2655_I2C_ADDRESS 0x40 // Float Float GND // #define LTC2655_I2C_ADDRESS 0x41 // Float Float Float // #define LTC2655_I2C_ADDRESS 0x42 // Float Float Vcc // #define LTC2655_I2C_ADDRESS 0x43 // Float Vcc GND // #define LTC2655_I2C_ADDRESS 0x50 // Float Vcc Float // #define LTC2655_I2C_ADDRESS 0x51 // Float Vcc Vcc // #define LTC2655_I2C_ADDRESS 0x52 // Vcc GND GND // #define LTC2655_I2C_ADDRESS 0x53 // Vcc GND Float // #define LTC2655_I2C_ADDRESS 0x60 // Vcc GND Vcc // #define LTC2655_I2C_ADDRESS 0x61 // Vcc Float GND // #define LTC2655_I2C_ADDRESS 0x62 // Vcc Float Float // #define LTC2655_I2C_ADDRESS 0x63 // Vcc Float Vcc // #define LTC2655_I2C_ADDRESS 0x70 // Vcc Vcc GND // #define LTC2655_I2C_ADDRESS 0x71 // Vcc Vcc Float // #define LTC2655_I2C_ADDRESS 0x72 // Vcc Vcc Vcc #define LTC2655_I2C_GLOBAL_ADDRESS 0x73 //! @} //! @name LTC2655 Command Codes //! @{ //! OR'd together with the DAC address to form the command byte #define LTC2655_CMD_WRITE 0x00 // Write to input register n #define LTC2655_CMD_UPDATE 0x10 // Update (power up) DAC register n #define LTC2655_CMD_WRITE_UPDATE 0x30 // Write to input register n, update (power up) all #define LTC2655_CMD_POWER_DOWN 0x40 // Power down n #define LTC2655_CMD_POWER_DOWN_ALL 0x50 // Power down chip (all DACs and reference) #define LTC2655_CMD_INTERNAL_REFERENCE 0x60 // Select internal reference (power up reference) #define LTC2655_CMD_EXTERNAL_REFERENCE 0x70 // Select external reference (power down internal reference) #define LTC2655_CMD_NO_OPERATION 0xF0 // No operation //! @} //! @name LTC2655 DAC Addresses //! @{ //! Which DAC to operate on #define LTC2655_DAC_A 0x00 #define LTC2655_DAC_B 0x01 #define LTC2655_DAC_C 0x02 #define LTC2655_DAC_D 0x03 #define LTC2655_DAC_ALL 0x0F //! @} // Command Example - write to DAC address D and update all. // dac_command = LTC2655_CMD_WRITE_UPDATE | LTC2655_DAC_D; //! Write a 16-bit dac_code to the LTC2655. //! @return ACK bit (0=acknowledge, 1=no acknowledge) int8_t LTC2655_write(uint8_t i2c_address, //!< I2C address of DAC uint8_t dac_command, //!< Command Nibble, left-justified, lower nibble set to zero uint8_t dac_address, //!< DAC Address Nibble, right justified, upper nibble set to zero uint16_t dac_code //!< 16-bit DAC code ); //! Calculate a LTC2655 DAC code given the desired output voltage //! @return The 16-bit code to send to the DAC uint16_t LTC2655_voltage_to_code(float dac_voltage, //!< Voltage to send to DAC float LTC2655_lsb, //!< LSB value int16_t LTC2655_offset //!< Offset ); //! Calculate the LTC2655 DAC output voltage given the DAC code, offset, and LSB value //! @return Calculated voltage float LTC2655_code_to_voltage(uint16_t dac_code, //!< DAC code float LTC2655_lsb, //!< LSB value int16_t LTC2655_offset //!< Offset ); //! Calculate the LTC2655 offset and LSB voltages given two measured voltages and their corresponding codes //! @return Void void LTC2655_calibrate(uint16_t dac_code1, //!< First DAC code uint16_t dac_code2, //!< Second DAC code float voltage1, //!< First voltage float voltage2, //!< Second voltage float *LTC2655_lsb, //!< Returns resulting LSB int16_t *LTC2655_offset //!< Returns resulting Offset ); #endif // LTC2655_H