st7920.cpp

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#include "st7920.h"
#include "esphome/components/display/display_buffer.h"
#include "esphome/core/application.h"
#include "esphome/core/log.h"
 
namespace esphome::st7920 {
 
static const char *const TAG = "st7920";
 
// ST7920 COMMANDS
static const uint8_t LCD_DATA = 0xFA;
static const uint8_t LCD_COMMAND = 0xF8;
static const uint8_t LCD_CLS = 0x01;
static const uint8_t LCD_HOME = 0x02;
static const uint8_t LCD_ADDRINC = 0x06;
static const uint8_t LCD_DISPLAYON = 0x0C;
static const uint8_t LCD_DISPLAYOFF = 0x08;
static const uint8_t LCD_CURSORON = 0x0E;
static const uint8_t LCD_CURSORBLINK = 0x0F;
static const uint8_t LCD_BASIC = 0x30;
static const uint8_t LCD_GFXMODE = 0x36;
static const uint8_t LCD_EXTEND = 0x34;
static const uint8_t LCD_TXTMODE = 0x34;
static const uint8_t LCD_STANDBY = 0x01;
static const uint8_t LCD_SCROLL = 0x03;
static const uint8_t LCD_SCROLLADDR = 0x40;
static const uint8_t LCD_ADDR = 0x80;
static const uint8_t LCD_LINE0 = 0x80;
static const uint8_t LCD_LINE1 = 0x90;
static const uint8_t LCD_LINE2 = 0x88;
static const uint8_t LCD_LINE3 = 0x98;
 
void ST7920::setup() {
  this->dump_config();
  this->spi_setup();
  this->init_internal_(this->get_buffer_length_());
  display_init_();
}
 
void ST7920::command_(uint8_t value) {
  this->enable();
  this->send_(LCD_COMMAND, value);
  this->disable();
}
 
void ST7920::data_(uint8_t value) {
  this->enable();
  this->send_(LCD_DATA, value);
  this->disable();
}
 
void ST7920::send_(uint8_t type, uint8_t value) {
  this->write_byte(type);
  this->write_byte(value & 0xF0);
  this->write_byte(value << 4);
}
 
void ST7920::goto_xy_(uint16_t x, uint16_t y) {
  if (y >= 32 && y < 64) {
    y -= 32;
    x += 8;
  } else if (y >= 64 && y < 64 + 32) {
    y -= 32;
    x += 0;
  } else if (y >= 64 + 32 && y < 64 + 64) {
    y -= 64;
    x += 8;
  }
  this->command_(LCD_ADDR | y);  // 6-bit (0..63)
  this->command_(LCD_ADDR | x);  // 4-bit (0..15)
}
 
void HOT ST7920::write_display_data() {
  int i, j;
  uint8_t b;
  int width_bytes = this->get_width_internal() / 8;
  int half_height = this->get_height_internal() / 2;
  for (j = 0; j < half_height; j++) {
    this->goto_xy_(0, j);
    this->enable();
    for (i = 0; i < width_bytes; i++) {
      b = this->buffer_[i + j * width_bytes];
      this->send_(LCD_DATA, b);
    }
    for (i = 0; i < width_bytes; i++) {
      b = this->buffer_[i + (j + half_height) * width_bytes];
      this->send_(LCD_DATA, b);
    }
    this->disable();
    App.feed_wdt();
  }
}
 
void ST7920::fill(Color color) {
  // If clipping is active, fall back to base implementation
  if (this->get_clipping().is_set()) {
    Display::fill(color);
    return;
  }
 
  uint8_t fill = color.is_on() ? 0xFF : 0x00;
  memset(this->buffer_, fill, this->get_buffer_length_());
}
 
void ST7920::dump_config() {
  LOG_DISPLAY("", "ST7920", this);
  LOG_PIN("  CS Pin: ", this->cs_);
  ESP_LOGCONFIG(TAG,
                "  Height: %d\n"
                "  Width: %d",
                this->height_, this->width_);
}
 
float ST7920::get_setup_priority() const { return setup_priority::PROCESSOR; }
 
void ST7920::update() {
  this->clear();
  if (this->writer_local_.has_value())  // call lambda function if available
    (*this->writer_local_)(*this);
  this->write_display_data();
}
 
int ST7920::get_width_internal() { return this->width_; }
 
int ST7920::get_height_internal() { return this->height_; }
 
size_t ST7920::get_buffer_length_() {
  return size_t(this->get_width_internal()) * size_t(this->get_height_internal()) / 8u;
}
 
void HOT ST7920::draw_absolute_pixel_internal(int x, int y, Color color) {
  if (x >= this->get_width_internal() || x < 0 || y >= this->get_height_internal() || y < 0) {
    return;
  }
  int width = this->get_width_internal() / 8u;
  if (color.is_on()) {
    this->buffer_[y * width + x / 8] |= (0x80 >> (x & 7));
  } else {
    this->buffer_[y * width + x / 8] &= ~(0x80 >> (x & 7));
  }
}
 
void ST7920::display_init_() {
  ESP_LOGD(TAG, "Initializing display");
  this->command_(LCD_BASIC);      // 8bit mode
  this->command_(LCD_BASIC);      // 8bit mode
  this->command_(LCD_CLS);        // clear screen
  delay(12);                      // >10 ms delay
  this->command_(LCD_ADDRINC);    // cursor increment right no shift
  this->command_(LCD_DISPLAYON);  // D=1, C=0, B=0
  this->command_(LCD_EXTEND);     // LCD_EXTEND);
  this->command_(LCD_GFXMODE);    // LCD_GFXMODE);
  this->write_display_data();
}
 
}  // namespace esphome::st7920