mcp48x2_dac.h

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/**
 * @file mcp48x2_dac.h
 * @ingroup mcp48x2
 * @author Jason Duffy
 * @date 4th March 2022
 * @brief Driver for the MCP4812 10 bit DAC (digital to analog converter) chip.
 * @bug No known bugs. 
 * @details This file provides the basic low-level functionality for the
 * MCP4812 10 bit DAC from Microchip. This driver currently only allows for a
 * single DAC to be used, but this might be improved on at a later date. This
 * driver was written using the datasheet for the Microchip MCP4812 chip, which
 * can be found at the link below.
 * @see https://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf
 */
 
#ifndef MCP_FOUR_EIGHT_X_TWO_DOT_H
#define MCP_FOUR_EIGHT_X_TWO_DOT_H
 
#include <stdbool.h>
#include <stdint.h>
 
#define DAC_CHANNEL_A       true
#define DAC_CHANNEL_B       false
 
 
/**
 * Enumerated constants to select the DAC model number. 
 */
typedef enum 
{
    mcp4802,
    mcp4812,
    mcp4822
} model_num_t;
 
 
/**
 * Struct for config values for each channel - this is only to be used as a
 * nested struct within the dac_config_t struct. 
 */
typedef struct
{
    bool gain_low;    // true = LOW (0 - 2048mV), false = HIGH (0 - 4096mV).
    bool active;      // true = Channel active, false = channel shutdown.
    uint16_t level;   // Value to be output on channel A.
} dac_channel_t;
 
 
/**
 * Config struct for DAC. Instantiate this object and assign values to it's 
 * members before passing it's address intp the init_dac() function. 
 */
typedef struct
{
    model_num_t model; // mcp4802, mcp4812 or mcp4822.
    bool sync_manually; // true = manual sync, false = sync automatically.
    dac_channel_t channel_a; // Config data members for channel A.
    dac_channel_t channel_b; // Config data members for channel B.
} dac_config_t;
 
 
/**
 * Initialisation routine (run once at startup).
 * This function is to be called before using any other DAC functions.
 * Instantiate the dac_config_t object first then pass it's address into and
 * call init_lcd() before using any other lcd functions.
 * @param p_config is a pointer to the dac_config_t object.
 */
void init_dac(dac_config_t *p_config);
 
 
/**
 * Sends a new millivolts value to be output on DAC (Along with config
 * settings). For 8 or 10 bit models only.
 * @param channel_a: true = Channel A, false = Channel B.
 * @param millivolts: mV value to be output by DAC. Ensure that this value
 * doesn't exceed the maxixum for the DAC model and gain setting. 
 */
void dac_set_voltage(bool channel_a, uint16_t millivolts);
 
 
/**
 * Sends a new millivolts value to be output on DAC (Along with config
 * settings). For 12 bit models only. 
 * @param channel_a: true = Channel A, false = Channel B.
 * @param millivolts: mV value to be output by DAC. Ensure that this value
 * doesn't exceed the maxixum for the DAC model and gain setting.
 * @param fractional: true = millivolts value has 0.5mV added to it. Only to be
 * used when gain_low is true. 
 */
void dac_set_voltage_12_bit(bool channel_a,
                            uint16_t millivolts,
                            bool fractional);
 
 
/**
 * Applies new config settings. This function takes updated config settings for
 * both channels of DAC, then re-sends data so that the new settings take
 * effect.
 */
void dac_reconfigure(void);
 
 
/**
 * Pulses LDAC pin low for a brief time (1uS). When sync_manually is true, call
 * this function to latch both config settings and new voltage value into both
 * channels of DAC simultaneously. 
 */
void pulse_latch(void);
 
#endif // MCP_FOUR_EIGHT_X_TWO_DOT_H
 
 
/*** end of file ***/