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Code Issues Releases Wiki Activity

Add backlight handling for lcd_pcf8574

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Switch the backlight on or off by calling id(mydisplay).backlight()
or id(mydisplay).no_backlight() in lamda functions (assuming mydisplay
is the custom id for the LCD).
This commit is contained in:
Attila Darazs 2019-05-30 17:15:40 +02:00
parent 1ce257c721
commit 34e25d19b1
2 changed files with 19 additions and 2 deletions
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16
esphome/components/lcd_pcf8574/pcf8574_display.cpp
View File

@ -6,9 +6,13 @@ namespace lcd_pcf8574 {
static const char *TAG = "lcd_pcf8574"; static const char *TAG = "lcd_pcf8574";
static const uint8_t LCD_DISPLAY_BACKLIGHT_ON = 0x08;
static const uint8_t LCD_DISPLAY_BACKLIGHT_OFF = 0x00;
void PCF8574LCDDisplay::setup() { void PCF8574LCDDisplay::setup() {
ESP_LOGCONFIG(TAG, "Setting up PCF8574 LCD Display..."); ESP_LOGCONFIG(TAG, "Setting up PCF8574 LCD Display...");
if (!this->write_bytes(0x08, nullptr, 0)) { this->backlight_value_ = LCD_DISPLAY_BACKLIGHT_ON;
if (!this->write_bytes(this->backlight_value_, nullptr, 0)) {
this->mark_failed(); this->mark_failed();
return; return;
} }
@ -29,7 +33,7 @@ void PCF8574LCDDisplay::write_n_bits(uint8_t value, uint8_t n) {
// Ugly fix: in the super setup() with n == 4 value needs to be shifted left // Ugly fix: in the super setup() with n == 4 value needs to be shifted left
value <<= 4; value <<= 4;
} }
uint8_t data = value | 0x08; // Enable backlight uint8_t data = value | this->backlight_value_; // Set backlight state
this->write_bytes(data, nullptr, 0); this->write_bytes(data, nullptr, 0);
// Pulse ENABLE // Pulse ENABLE
this->write_bytes(data | 0x04, nullptr, 0); this->write_bytes(data | 0x04, nullptr, 0);
@ -41,6 +45,14 @@ void PCF8574LCDDisplay::send(uint8_t value, bool rs) {
this->write_n_bits((value & 0xF0) | rs, 0); this->write_n_bits((value & 0xF0) | rs, 0);
this->write_n_bits(((value << 4) & 0xF0) | rs, 0); this->write_n_bits(((value << 4) & 0xF0) | rs, 0);
} }
void PCF8574LCDDisplay::backlight() {
this->backlight_value_ = LCD_DISPLAY_BACKLIGHT_ON;
this->write_bytes(this->backlight_value_, nullptr, 0);
}
void PCF8574LCDDisplay::no_backlight() {
this->backlight_value_ = LCD_DISPLAY_BACKLIGHT_OFF;
this->write_bytes(this->backlight_value_, nullptr, 0);
}
} // namespace lcd_pcf8574 } // namespace lcd_pcf8574
} // namespace esphome } // namespace esphome

5
esphome/components/lcd_pcf8574/pcf8574_display.h
View File

@ -11,11 +11,16 @@ class PCF8574LCDDisplay : public lcd_base::LCDDisplay, public i2c::I2CDevice {
public: public:
void setup() override; void setup() override;
void dump_config() override; void dump_config() override;
void backlight();
void no_backlight();
protected: protected:
bool is_four_bit_mode() override { return true; } bool is_four_bit_mode() override { return true; }
void write_n_bits(uint8_t value, uint8_t n) override; void write_n_bits(uint8_t value, uint8_t n) override;
void send(uint8_t value, bool rs) override; void send(uint8_t value, bool rs) override;
// Stores the current state of the backlight.
uint8_t backlight_value_;
}; };
} // namespace lcd_pcf8574 } // namespace lcd_pcf8574