Updated Mcp3008 to support reference_voltage and voltage_sampler::VoltageSampler (#1387)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/mcp3008/mcp3008.cpp

@@ -18,16 +18,15 @@ void MCP3008::dump_config() {
   LOG_PIN("  CS Pin:", this->cs_);
 }
 
-float MCP3008::read_data_(uint8_t pin) {
-  uint8_t data_msb = 0;
-  uint8_t data_lsb = 0;
+float MCP3008::read_data(uint8_t pin) {
+  uint8_t data_msb, data_lsb = 0;
 
   uint8_t command = ((0x01 << 7) |          // start bit
                      ((pin & 0x07) << 4));  // channel number
 
   this->enable();
-
   this->transfer_byte(0x01);
+
   data_msb = this->transfer_byte(command) & 0x03;
   data_lsb = this->transfer_byte(0x00);
 
@@ -35,18 +34,29 @@ float MCP3008::read_data_(uint8_t pin) {
 
   int data = data_msb << 8 | data_lsb;
 
-  return data / 1024.0f;
+  return data / 1023.0f;
 }
 
-MCP3008Sensor::MCP3008Sensor(MCP3008 *parent, std::string name, uint8_t pin)
+MCP3008Sensor::MCP3008Sensor(MCP3008 *parent, std::string name, uint8_t pin, float reference_voltage)
     : PollingComponent(1000), parent_(parent), pin_(pin) {
   this->set_name(name);
+  this->reference_voltage_ = reference_voltage;
 }
+
+float MCP3008Sensor::get_setup_priority() const { return setup_priority::DATA; }
+
 void MCP3008Sensor::setup() { LOG_SENSOR("", "Setting up MCP3008 Sensor '%s'...", this); }
-void MCP3008Sensor::update() {
-  float value_v = this->parent_->read_data_(pin_);
-  this->publish_state(value_v);
+void MCP3008Sensor::dump_config() {
+  ESP_LOGCONFIG(TAG, "MCP3008Sensor:");
+  ESP_LOGCONFIG(TAG, "  Pin: %u", this->pin_);
+  ESP_LOGCONFIG(TAG, "  Reference Voltage: %.2fV", this->reference_voltage_);
 }
+float MCP3008Sensor::sample() {
+  float value_v = this->parent_->read_data(pin_);
+  value_v = (value_v * this->reference_voltage_);
+  return value_v;
+}
+void MCP3008Sensor::update() { this->publish_state(this->sample()); }
 
 }  // namespace mcp3008
 }  // namespace esphome

esphome/components/mcp3008/mcp3008.h

@@ -4,38 +4,41 @@
 #include "esphome/core/esphal.h"
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/spi/spi.h"
+#include "esphome/components/voltage_sampler/voltage_sampler.h"
 
 namespace esphome {
 namespace mcp3008 {
 
-class MCP3008Sensor;
-
 class MCP3008 : public Component,
                 public spi::SPIDevice<spi::BIT_ORDER_MSB_FIRST, spi::CLOCK_POLARITY_LOW, spi::CLOCK_PHASE_LEADING,
-                                      spi::DATA_RATE_1MHZ> {  // At 3.3V 2MHz is too fast 1.35MHz is about right
+                                      spi::DATA_RATE_75KHZ> {  // Running at the slowest max speed supported by the
+                                                               // mcp3008. 2.7v = 75ksps
  public:
   MCP3008() = default;
 
   void setup() override;
   void dump_config() override;
   float get_setup_priority() const override;
+  float read_data(uint8_t pin);
 
  protected:
-  float read_data_(uint8_t pin);
-
-  friend class MCP3008Sensor;
 };
 
-class MCP3008Sensor : public PollingComponent, public sensor::Sensor {
+class MCP3008Sensor : public PollingComponent, public sensor::Sensor, public voltage_sampler::VoltageSampler {
  public:
-  MCP3008Sensor(MCP3008 *parent, std::string name, uint8_t pin);
+  MCP3008Sensor(MCP3008 *parent, std::string name, uint8_t pin, float reference_voltage);
 
+  void set_reference_voltage(float reference_voltage) { reference_voltage_ = reference_voltage; }
   void setup() override;
   void update() override;
+  void dump_config() override;
+  float get_setup_priority() const override;
+  float sample() override;
 
  protected:
   MCP3008 *parent_;
   uint8_t pin_;
+  float reference_voltage_;
 };
 
 }  // namespace mcp3008

esphome/components/mcp3008/sensor.py

@@ -1,23 +1,29 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
-from esphome.components import sensor
+from esphome.components import sensor, voltage_sampler
 from esphome.const import CONF_ID, CONF_NUMBER, CONF_NAME
 from . import mcp3008_ns, MCP3008
 
+AUTO_LOAD = ['voltage_sampler']
+
 DEPENDENCIES = ['mcp3008']
 
-MCP3008Sensor = mcp3008_ns.class_('MCP3008Sensor', sensor.Sensor, cg.PollingComponent)
-
+MCP3008Sensor = mcp3008_ns.class_('MCP3008Sensor', sensor.Sensor, cg.PollingComponent,
+                                  voltage_sampler.VoltageSampler)
+CONF_REFERENCE_VOLTAGE = 'reference_voltage'
 CONF_MCP3008_ID = 'mcp3008_id'
 
 CONFIG_SCHEMA = sensor.SENSOR_SCHEMA.extend({
     cv.GenerateID(): cv.declare_id(MCP3008Sensor),
     cv.GenerateID(CONF_MCP3008_ID): cv.use_id(MCP3008),
     cv.Required(CONF_NUMBER): cv.int_,
+    cv.Optional(CONF_REFERENCE_VOLTAGE, default='3.3V'): cv.voltage,
 }).extend(cv.polling_component_schema('1s'))
 
 
 def to_code(config):
     parent = yield cg.get_variable(config[CONF_MCP3008_ID])
-    var = cg.new_Pvariable(config[CONF_ID], parent, config[CONF_NAME], config[CONF_NUMBER])
+    var = cg.new_Pvariable(config[CONF_ID], parent, config[CONF_NAME],
+                           config[CONF_NUMBER], config[CONF_REFERENCE_VOLTAGE])
     yield cg.register_component(var, config)
+    yield sensor.register_sensor(var, config)

esphome/components/spi/spi.h

@@ -50,6 +50,7 @@ enum SPIClockPhase {
  */
 enum SPIDataRate : uint32_t {
   DATA_RATE_1KHZ = 1000,
+  DATA_RATE_75KHZ = 75000,
   DATA_RATE_200KHZ = 200000,
   DATA_RATE_1MHZ = 1000000,
   DATA_RATE_2MHZ = 2000000,

tests/test1.yaml

@@ -197,6 +197,10 @@ wled:
 
 adalight:
 
+mcp3008:
+  - id: 'mcp3008_hub'
+    cs_pin: GPIO12
+
 mcp23s08:
   - id: 'mcp23s08_hub'
     cs_pin: GPIO12
@@ -207,6 +211,7 @@ mcp23s17:
     cs_pin: GPIO12
     deviceaddress: 1
 
+
 sensor:
   - platform: adc
     pin: A0
@@ -801,6 +806,12 @@ sensor:
     id: ph_ezo
     address: 99
     unit_of_measurement: 'pH'
+  - platform: mcp3008
+    update_interval: 5s
+    mcp3008_id: 'mcp3008_hub'
+    id: freezer_temp_source
+    reference_voltage: 3.19
+    number: 0
 
 esp32_touch:
   setup_mode: False