Add digipot i2c control for MCP4018

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/felias-fogg/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

Marlin/digipot_mcp4451.cpp

 
 #include "MarlinConfig.h"
 
-#if ENABLED(DIGIPOT_I2C)
+#if ENABLED(DIGIPOT_I2C) && DISABLED(DIGIPOT_MCP4018)
 
 #include "Stream.h"
 #include "utility/twi.h"