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The AD5755 is is a quad, voltage and current output DAC that operates with a power supply range from −26.4 V to +33 V. On-chip dynamic power control minimizes package power dissipation in current mode. This is achieved by regulating the voltage on the output driver from 7.4 V to 29.5 V using a dc-to-dc boost converter optimized for minimum on chip power dissipation.
The part uses a versatile 3-wire serial interface that operates at clock rates of up to 30 MHz and is compatible with standard SPI, QSPI™, MICROWIRE™, DSP, and microcontroller inter-face standards. The interface also features optional CRC-8 packet error checking, as well as a watchdog timer that monitors activity on the interface.
The goal of this project (Microcontroller No-OS) is to be able to provide reference projects for lower end processors, which can't run Linux, or aren't running a specific operating system, to help those customers using microcontrollers with ADI parts. Here you can find a generic driver which can be used as a base for any microcontroller platform and also specific drivers for Renesas platforms.
The driver contains two parts:
The Communication Driver has a standard interface, so the AD5755 driver can be used exactly as it is provided.
There are three functions which are called by the AD5755 driver:
SPI driver architecture
The following functions are implemented in this version of AD5755 driver:
|unsigned char AD5755_Init(void)||Initializes the device and powers-up all channels.|
|long AD5755_GetRegisterValue(unsigned char registerAddress)||Reads the value of a register.|
|unsigned short AD5755_SetRegisterValue(unsigned char registerAddress, unsigned char channel, unsigned long registerValue)||Writes data into a register.|
|void AD5755_Software_Reset(void)||Performs a software reset to the device.|
|void AD5755_WatchDogSetup(unsigned char wtdEnable, unsigned char timeout)||Enables/Disables watchdog timer and sets the timeout period.|
|void AD5755_FeedWatchDogTimer(void)||Writes a “service pulse” to the AD5755 watchdog timer when enabled.|
|void AD5755_SetControlRegisters(unsigned char ctrlRegAddress, unsigned char channel,unsigned short regValue)||Configures one of the control registers.|
|unsigned char AD5755_CheckCrc(unsigned char* data, unsigned char bytesNumber)||Computes the CRC for a data buffer.|
|void AD5755_SetChannelPower(unsigned char channel, unsigned char pwrStatus)||Allows power-up/down of the dc-to-dc converter, DAC and internal amplifiers for the selected channel.|
|void AD5755_SetChannelRange(unsigned char channel, unsigned char range)||Sets the range of a channel.|
|void AD5755_ChannelClearEnable(unsigned char channel, unsigned char clearEn)||Selects if the channel clears when CLEAR pin is activated.|
|void AD5755_SlewRateCtrl(char channel, char srEn, char updtFreq, char stepSize)||Configures the Digital Slew Rate Control.|
|float AD5755_SetVoltage(unsigned char channel, float voltage)||Sets the output voltage of a channel.|
|float AD5755_SetCurrent(unsigned char channel, float mACurrent)||Sets the output current of a channel.|
This section contains a description of the steps required to run the AD5755 demonstration project on a Renesas RL78G13 platform.
An EVAL-AD5755SDZ has to be interfaced with the Renesas Demonstration Kit (RDK) for RL78G13:
EVAL-AD5755SDZ J11 Pin 1(DVDD) → YRDKRL78G13 J11 connector Pin 6 EVAL-AD5755SDZ J11 Pin 2(DGND) → YRDKRL78G13 J11 connector Pin 5 EVAL-AD5755SDZ J11 Pin 3(SYNC) → YRDKRL78G13 J11 connector Pin 1 EVAL-AD5755SDZ J11 Pin 4(SCLK) → YRDKRL78G13 J11 connector Pin 4 EVAL-AD5755SDZ J11 Pin 5(SDIN) → YRDKRL78G13 J11 connector Pin 3 EVAL-AD5755SDZ J11 Pin 6(SDO) → YRDKRL78G13 J11 connector Pin 2 EVAL-AD5755SDZ J11 Pin 7(LDAC) → YRDKRL78G13 J11 connector Pin 9 EVAL-AD5755SDZ J11 Pin 8(CLEAR) → YRDKRL78G13 J11 connector Pin 7 EVAL-AD5755SDZ J11 Pin 9(POC) → YRDKRL78G13 J11 connector Pin 8 EVAL-AD5755SDZ J11 Pin 10(RESET) → YRDKRL78G13 J11 connector Pin 10
The reference project outputs a square signal on channel A, and DC voltage signals on channels B, C and D.
This section presents the steps for developing a software application that will run on the Renesas Demo Kit for RL78G13 for controlling and monitoring the operation of the ADI part.