marlin/Marlin/digipot_mcp4018.cpp

/**
 * Marlin 3D Printer Firmware
 * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
 *
 * Based on Sprinter and grbl.
 * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "MarlinConfig.h"

#if ENABLED(DIGIPOT_I2C) && ENABLED(DIGIPOT_MCP4018)

#include "Stream.h"
#include "utility/twi.h"
#include <SlowSoftI2CMaster.h>  //https://github.com/stawel/SlowSoftI2CMaster

// Settings for the I2C based DIGIPOT (MCP4018) based on WT150

#define DIGIPOT_I2C_ADDRESS             0x2F

#define DIGIPOT_A4988_Rsx               0.250
#define DIGIPOT_A4988_Vrefmax           5.0
#define DIGIPOT_A4988_MAX_VALUE         127

#define DIGIPOT_A4988_Itripmax(Vref)    ((Vref)/(8.0*DIGIPOT_A4988_Rsx))

#define DIGIPOT_A4988_FACTOR            (DIGIPOT_A4988_MAX_VALUE/DIGIPOT_A4988_Itripmax(DIGIPOT_A4988_Vrefmax))
//TODO: MAX_CURRENT -0.5A ?? (currently set to 2A, max possible current 2.5A)
#define DIGIPOT_A4988_MAX_CURRENT       (DIGIPOT_A4988_Itripmax(DIGIPOT_A4988_Vrefmax) - 0.5)

static byte current_to_wiper(float current) {
  return byte(ceil(float((DIGIPOT_A4988_FACTOR * current))));
}

static uint8_t sda_pins[DIGIPOT_I2C_NUM_CHANNELS] = {
  DIGIPOTS_I2C_SDA_X,
  DIGIPOTS_I2C_SDA_Y,
  DIGIPOTS_I2C_SDA_Z,
  DIGIPOTS_I2C_SDA_E0,
  DIGIPOTS_I2C_SDA_E1,
};

static SlowSoftI2CMaster pots[DIGIPOT_I2C_NUM_CHANNELS] = {
  SlowSoftI2CMaster { sda_pins[0], DIGIPOTS_I2C_SCL },
  SlowSoftI2CMaster { sda_pins[1], DIGIPOTS_I2C_SCL },
  SlowSoftI2CMaster { sda_pins[2], DIGIPOTS_I2C_SCL },
  SlowSoftI2CMaster { sda_pins[3], DIGIPOTS_I2C_SCL },
  SlowSoftI2CMaster { sda_pins[4], DIGIPOTS_I2C_SCL }
};

static void i2c_send(int channel, byte v) {
  if (WITHIN(channel, 0, DIGIPOT_I2C_NUM_CHANNELS - 1)) {
    pots[channel].i2c_start(((DIGIPOT_I2C_ADDRESS) << 1) | I2C_WRITE);
    pots[channel].i2c_write(v);
    pots[channel].i2c_stop();
  }
}

// This is for the MCP4018 I2C based digipot
void digipot_i2c_set_current(int channel, float current) {
  current = min(max(current, 0.0f), float(DIGIPOT_A4988_MAX_CURRENT));

  i2c_send(channel, current_to_wiper(current));
}

void digipot_i2c_init() {
  const float digipot_motor_current[] = DIGIPOT_I2C_MOTOR_CURRENTS;

  for (uint8_t i = 0; i < DIGIPOT_I2C_NUM_CHANNELS; i++)
    pots[i].i2c_init();

  // setup initial currents as defined in Configuration_adv.h
  for (uint8_t i = 0; i < COUNT(digipot_motor_current); i++)
    digipot_i2c_set_current(i, digipot_motor_current[i]);
}

#endif // DIGIPOT_I2C && DIGIPOT_MCP4018