voxlpm.hpp

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/**
 * @file voxlpm.hpp
 *
 * Shared defines for the voxlpm (QTY2 LTC2946) driver.
 *
 * This is roughly what's goin on:
 *
 *             +~~~~~~~~~~~~~~+
 *  VBATT -----| RSENSE_VBATT | ----------+---------------------> VBATT TO ESCS
 *     |       +~~~~~~~~~~~~~~+           |
 *     |              |          +--------+------+
 *     +----+    +----+          | 5V REGULATOR  |
 *          |    |               +--------+------+
 *          |    |                        |   +~~~~~~~~~~~~~~+
 *          |    |                        +---| RSENSE_5VOUT |---> 5VDC TO COMPUTE
 *          |    |                        |   +~~~~~~~~~~~~~~+
 *          |    |                        |         |
 *         V|    |A                      V|         |A
 *     #################              #################
 *     # LTC2946, 0x6a #              # LTC2946, 0x6b #
 *     #################              #################
 *
 *     Publishes:                     Publishes:
 *     - ORB_ID(battery_status)
 *     - ORB_ID(power_monitor)        - ORB_ID(power_monitor)
 *
 */
#pragma once

#include <drivers/device/i2c.h>
#include <perf/perf_counter.h>

#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>

#include <battery/battery.h>

#include <uORB/uORB.h>
#include <uORB/topics/battery_status.h>
#include <uORB/topics/power_monitor.h>

/*
 * Note that these are unshifted addresses.
 */
#define VOXLPM_LTC2946_ADDR_VBATT       0x6a // 0x6a  = 0xd4 >> 1
#define VOXLPM_LTC2946_ADDR_P5VD        0x6b // 0x6b  = 0xd6 >> 1

#define VOXLPM_LTC2946_CTRLA_REG        0x00
#define VOXLPM_LTC2946_CTRLB_REG        0x01

#define VOXLPM_LTC2946_POWER_MSB2_REG       0x05
#define VOXLPM_LTC2946_CTRLB_MSG1_REG       0x06
#define VOXLPM_LTC2946_CTRLB_LSB_REG        0x07

#define VOXLPM_LTC2946_DELTA_SENSE_MSB_REG  0x14
#define VOXLPM_LTC2946_DELTA_SENSE_LSB_REG  0x15

#define VOXLPM_LTC2946_VIN_MSB_REG      0x1E
#define VOXLPM_LTC2946_VIN_LSB_REG      0x1F

/*
 * CTRLA (Address 0x00 - LTC2946_CTRLA_REG)
 *
 *   7 - [ADIN Configuration]
 *       0  --> ADIN Measured with Respect to GND
 * 6:5 - [Offset Calibratoin Configuration]
 *       00 --> Every Conversion
 * 4:3 - [Voltage Selection]
 *       11 --> SENSE+
 * 2:0 - [Channel Configuration]
 *       000 --> Alternate Voltage, Current Measurement
 */
#define DEFAULT_CTRLA_REG_VAL           0x18

/*
 * CTRLB (Address 0x01 - LTC2946_CTRLA_REG)
 *
 *   7 - [!ALERT Clear Enable ]
 *       0  --> Disable
 *   6 - [Shutdown]
 *       0  --> Power-Up
 *   5 - [Cleared on Read Control]
 *       0  --> Registers Not Affected by Reading
 *   4 - [Stuck Bus Timeout Auto Wake-Up]
 *       0 --> Disable
 * 3:2 - [Enable Accumulation]
 *       00 --> Accumulate
 * 1:0 - [Auto-Reset Mode/Reset]
 *       01 --> Enable Auto-Reset
 */
#define DEFAULT_CTRLB_REG_VAL           0x01

/* 12 bits */
#define VOXLPM_LTC2946_RESOLUTION       4095.0f

/* VFS Full-Scale Voltage, SENSE+ */
#define VOXLPM_LTC2946_VFS_SENSE        102.4f

/* VFS Full-Scale Voltage, delta sense */
#define VOXLPM_LTC2946_VFS_DELTA_SENSE      0.1024f

/* Power sense resistor for battery current */
#define VOXLPM_RSENSE_VBATT         0.0005f

/* Power sense resistor for 5VDC output current */
#define VOXLPM_RSENSE_5VOUT         0.005f

enum VOXLPM_CH_TYPE {
    VOXLPM_CH_TYPE_VBATT = 0,
    VOXLPM_CH_TYPE_P5VDC
};

class VOXLPM : public device::I2C, public px4::ScheduledWorkItem
{
public:
    VOXLPM(const char *path, int bus, int address, VOXLPM_CH_TYPE ch_type);
    virtual ~VOXLPM();

    virtual int     init();
    void            print_info();

private:
    unsigned        _meas_interval{100000}; // 100ms
    void            Run() override;
    void            start();
    void            stop();
    int             measure();

    perf_counter_t      _sample_perf;

    orb_advert_t        _bat_pub_topic;
    orb_advert_t        _pm_pub_topic;

    struct battery_status_s _bat_status;
    struct power_monitor_s  _pm_status;

    VOXLPM_CH_TYPE      _ch_type;
    float           _voltage;
    float           _amperage;
    float           _rsense;

    Battery         _battery;

    uint8_t         read_reg(uint8_t addr);
    int             read_reg_buf(uint8_t addr, uint8_t *buf, uint8_t len);
    int             write_reg(uint8_t value, uint8_t addr);
};