Added files missing from earlier commit.

Marlin/src/lcd/dogm/ultralcd_impl_st7920_lite_status_screen.h

@@ -0,0 +1,247 @@
+/*
+ * Lightweight Status Screen for the RepRapDiscount Full
+ * Graphics Smart Controller (ST7920-based 128x64 LCD)
+ *
+ * (c) 2017 Aleph Objects, Inc.
+ *
+ * The code in this page is free software: you can
+ * redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GNU GPL) as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option)
+ * any later version.  The code is distributed WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.
+ *
+ */
+
+#ifndef ULTRALCD_ST7920_LITE_STATUS_H
+#define ULTRALCD_ST7920_LITE_STATUS_H
+
+class ST7920_Lite_Status_Screen {
+  private:
+    static struct st7920_state_t {
+      uint8_t synced   : 1; // Whether a sync has been sent
+      uint8_t cmd      : 1; // Whether the sync was cmd or data
+      uint8_t extended : 1;
+      uint8_t graphics : 1;
+      uint8_t sa       : 1;
+    } current_bits;
+
+    static void cs();
+    static void ncs();
+    static void sync_cmd();
+    static void sync_dat();
+    static void write_byte(uint8_t w);
+
+    static void cmd(uint8_t cmd);
+    static void begin_data();
+    static void write_word(uint16_t w);
+    static void write_str(const char *str);
+    static void write_str(const char *str, uint8_t len);
+    static void write_str_P(const char *str);
+    static void write_str(progmem_str str);
+    static void write_number(uint8_t value, uint8_t digits=3);
+
+    static void _extended_function_set(bool extended, bool graphics);
+    static void _scroll_or_addr_select(bool sa);
+    static void reset_state_from_unknown();
+
+    static void home();
+    static void display_status(bool display_on, bool cursor_on, bool blink_on);
+    static void extended_function_set(bool extended);
+    static void graphics(bool graphics);
+    static void entry_mode_select(bool ac_increase, bool shift);
+    static void scroll_or_addr_select(bool sa);
+    static void set_ddram_address(uint8_t addr);
+    static void set_cgram_address(uint8_t addr);
+    static void set_gdram_address(uint8_t x, uint8_t y);
+
+    static void clear();
+    static void clear_ddram();
+    static void clear_gdram();
+
+    static void load_cgram_icon(uint16_t addr, const void *data);
+    static void draw_gdram_icon(uint8_t x, uint8_t y, const void *data);
+
+    static uint8_t string_checksum(const char *str);
+
+  protected:
+    static void draw_static_elements();
+    static void draw_progress_bar(uint8_t value);
+    static void draw_fan_icon(bool whichIcon);
+    static void draw_heat_icon(bool whichIcon, bool heating);
+    static void draw_extruder_1_temp(uint8_t temp, uint8_t target);
+    static void draw_extruder_2_temp(uint8_t temp, uint8_t target);
+    static void draw_bed_temp(uint8_t temp, uint8_t target);
+    static void draw_fan_speed(uint8_t value);
+    static void draw_print_time(uint32_t elapsed);
+    static void draw_feedrate_percentage(uint8_t percentage);
+    static void draw_status_message(const unsigned char *str);
+    static void draw_position(const float x, const float y, const float z, bool position_known = true);
+
+    static bool indicators_changed();
+    static bool position_changed();
+    static bool blink_changed();
+    static bool status_changed();
+
+    static void update_indicators(bool forceUpdate);
+    static void update_position(bool forceUpdate, bool resetChecksum);
+    static void update_status_or_position(bool forceUpdate);
+    static void update_progress(bool forceUpdate);
+
+  public:
+    static void update(bool forceUpdate);
+    static void on_entry();
+    static void on_exit();
+    static void clear_text_buffer();
+};
+
+/************************** ICON DEFINITIONS *************************************/
+
+#define CGRAM_ICON_1_ADDR 0x00
+#define CGRAM_ICON_2_ADDR 0x10
+#define CGRAM_ICON_3_ADDR 0x20
+#define CGRAM_ICON_4_ADDR 0x30
+
+#define CGRAM_ICON_1_WORD 0x00
+#define CGRAM_ICON_2_WORD 0x02
+#define CGRAM_ICON_3_WORD 0x04
+#define CGRAM_ICON_4_WORD 0x06
+
+PROGMEM const uint16_t nozzle_icon[] = {
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000111111110000,
+  0b0001111111111000,
+  0b0001111111111000,
+  0b0001111111111000,
+  0b0000111111110000,
+  0b0000111111110000,
+  0b0001111111111000,
+  0b0001111111111000,
+  0b0001111111111000,
+  0b0000011111100000,
+  0b0000001111000000,
+  0b0000000110000000,
+  0b0000000000000000,
+  0b0000000000000000
+};
+
+PROGMEM const uint16_t bed_icon[] = {
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0111111111111110,
+  0b0111111111111110,
+  0b0000000000000000,
+  0b0000000000000000
+};
+
+PROGMEM const uint16_t heat1_icon[] = {
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0010001000100000,
+  0b0001000100010000,
+  0b0000100010001000,
+  0b0000100010001000,
+  0b0001000100010000,
+  0b0010001000100000,
+  0b0010001000100000,
+  0b0001000100010000,
+  0b0000100010001000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000
+};
+
+PROGMEM const uint16_t heat2_icon[] = {
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000100010001000,
+  0b0000100010001000,
+  0b0001000100010000,
+  0b0010001000100000,
+  0b0010001000100000,
+  0b0001000100010000,
+  0b0000100010001000,
+  0b0000100010001000,
+  0b0001000100010000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000,
+  0b0000000000000000
+};
+
+PROGMEM const uint16_t fan1_icon[] = {
+  0b0000000000000000,
+  0b0111111111111110,
+  0b0111000000001110,
+  0b0110001111000110,
+  0b0100001111000010,
+  0b0100000110000010,
+  0b0101100000011010,
+  0b0101110110111010,
+  0b0101100000011010,
+  0b0100000110000010,
+  0b0100001111000010,
+  0b0110001111000110,
+  0b0111000000001110,
+  0b0111111111111110,
+  0b0000000000000000,
+  0b0000000000000000
+};
+
+PROGMEM const uint16_t fan2_icon[] = {
+  0b0000000000000000,
+  0b0111111111111110,
+  0b0111000000001110,
+  0b0110010000100110,
+  0b0100111001110010,
+  0b0101111001111010,
+  0b0100110000110010,
+  0b0100000110000010,
+  0b0100110000110010,
+  0b0101111001111010,
+  0b0100111001110010,
+  0b0110010000100110,
+  0b0111000000001110,
+  0b0111111111111110,
+  0b0000000000000000,
+  0b0000000000000000
+};
+
+PROGMEM const uint16_t feedrate_icon[] = {
+  0b0000000000000000,
+  0b0111111000000000,
+  0b0100000000000000,
+  0b0100000000000000,
+  0b0100000000000000,
+  0b0111111011111000,
+  0b0100000010000100,
+  0b0100000010000100,
+  0b0100000010000100,
+  0b0100000011111000,
+  0b0000000010001000,
+  0b0000000010000100,
+  0b0000000010000100,
+  0b0000000010000010,
+  0b0000000000000000,
+  0b0000000000000000
+};
+
+static void lcd_implementation_status_screen();
+static void lcd_in_status(bool inStatus);
+
+#endif // ULTRALCD_ST7920_LITE_STATUS_H

Marlin/src/lcd/dogm/ultralcd_impl_st7920_lite_status_screen_impl.h

@@ -0,0 +1,757 @@
+/*
+ * Lightweight Status Screen for the RepRapDiscount Full
+ * Graphics Smart Controller (ST7920-based 128x64 LCD)
+ *
+ * (c) 2017 Aleph Objects, Inc.
+ *
+ * The code in this page is free software: you can
+ * redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GNU GPL) as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option)
+ * any later version.  The code is distributed WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.
+ *
+ */
+
+ /* This is an implementation of a status screen for the RepRapDiscount
+  * Full Graphics Smart Controller using native ST7920 commands rather
+  * than using U8Glib.
+  *
+  * This alternative status screen makes use of the built-in character
+  * generation capabilities of the ST7920 to update the status screen
+  * with less SPI traffic and CPU use. In particular:
+  *
+  *    - The fan and bed animations are handled using custom characters
+  *      that are stored in CGRAM. This allows for the animation to be
+  *      updated by writing a single character to the text-buffer (DDRAM).
+  *
+  *    - All the information in the status screen is text that is written
+  *      to DDRAM, so the work of generating the bitmaps is offloaded to
+  *      the ST7920 rather than being render by U8Glib on the MCU.
+  *
+  *    - The graphics buffer (GDRAM) is only used for static graphics
+  *      elements (nozzle and feedrate bitmaps) and for the progress
+  *      bar, so updates are sporadic.
+  */
+
+#include "../../libs/duration_t.h"
+
+typedef const __FlashStringHelper *progmem_str;
+
+#include "ultralcd_impl_st7920_lite_status_screen.h"
+
+#define BUFFER_WIDTH   256
+#define BUFFER_HEIGHT  32
+
+#define DDRAM_LINE_1   0x00
+#define DDRAM_LINE_2   0x10
+#define DDRAM_LINE_3   0x08
+#define DDRAM_LINE_4   0x18
+
+ST7920_Lite_Status_Screen::st7920_state_t ST7920_Lite_Status_Screen::current_bits;
+
+void ST7920_Lite_Status_Screen::cmd(uint8_t cmd) {
+  if(!current_bits.synced || !current_bits.cmd) {
+    current_bits.synced = true;
+    current_bits.cmd    = true;
+    sync_cmd();
+  }
+  write_byte(cmd);
+}
+
+void ST7920_Lite_Status_Screen::begin_data() {
+  extended_function_set(false);
+  if(!current_bits.synced || current_bits.cmd) {
+    current_bits.synced = true;
+    current_bits.cmd    = false;
+    sync_dat();
+  }
+}
+
+void ST7920_Lite_Status_Screen::write_word(uint16_t w) {
+  write_byte((w >> 8) & 0xFF);
+  write_byte((w >> 0) & 0xFF);
+}
+
+void ST7920_Lite_Status_Screen::write_str(const char *str) {
+  while(*str) {
+     write_byte(*str++);
+  }
+}
+
+void ST7920_Lite_Status_Screen::write_str(const char *str, uint8_t len) {
+  while(*str && len--) {
+     write_byte(*str++);
+  }
+}
+
+void ST7920_Lite_Status_Screen::write_str_P(const char *str) {
+  const char *p_str = (const char *)str;
+  char c = pgm_read_byte_near(p_str++);
+  while(c) {
+     write_byte(c);
+     c = pgm_read_byte_near(p_str++);
+  }
+}
+
+void ST7920_Lite_Status_Screen::write_str(progmem_str str) {
+  write_str_P((const char*)str);
+}
+
+void ST7920_Lite_Status_Screen::write_number(uint8_t value, uint8_t digits=3) {
+  char  str[7];
+  const char *fmt;
+  switch(digits) {
+    case 6: fmt = PSTR("%6d"); break;
+    case 5: fmt = PSTR("%5d"); break;
+    case 4: fmt = PSTR("%4d"); break;
+    case 3: fmt = PSTR("%3d"); break;
+    case 2: fmt = PSTR("%2d"); break;
+    case 1: fmt = PSTR("%1d"); break;
+  }
+  sprintf_P(str,fmt,value);
+  write_str(str);
+}
+
+void ST7920_Lite_Status_Screen::display_status(bool display_on, bool cursor_on, bool blink_on) {
+  extended_function_set(false);
+  cmd(0b00001000 |
+    (display_on ? 0b0100 : 0) |
+    (cursor_on  ? 0b0010 : 0) |
+    (blink_on   ? 0b0001 : 0)
+  );
+}
+
+// Sets the extended and graphics bits simultaneously, regardless of
+// the current state. This is a helper function for extended_function_set()
+// and graphics()
+void ST7920_Lite_Status_Screen::_extended_function_set(bool extended, bool graphics) {
+  cmd(  0b00100000 |
+    (extended   ? 0b00000100 : 0) |
+    (graphics   ? 0b00000010 : 0)
+  );
+  current_bits.extended = extended;
+  current_bits.graphics = graphics;
+}
+
+void ST7920_Lite_Status_Screen::extended_function_set(bool extended) {
+  if(extended != current_bits.extended) {
+    _extended_function_set(extended, current_bits.graphics);
+  }
+}
+
+void ST7920_Lite_Status_Screen::graphics(bool graphics) {
+  if(graphics != current_bits.graphics) {
+    _extended_function_set(current_bits.extended, graphics);
+  }
+}
+
+void ST7920_Lite_Status_Screen::entry_mode_select(bool ac_increase, bool shift) {
+  extended_function_set(false);
+  cmd(0b00000100 |
+    (ac_increase ? 0b00000010 : 0) |
+    (shift       ? 0b00000001 : 0)
+  );
+}
+
+// Sets the sa bit regardless of the current state. This is a helper
+// function for scroll_or_addr_select()
+void ST7920_Lite_Status_Screen::_scroll_or_addr_select(bool sa) {
+  extended_function_set(true);
+  cmd(0b00100010 |
+    (sa   ? 0b000001 : 0)
+  );
+  current_bits.sa = sa;
+}
+
+void ST7920_Lite_Status_Screen::scroll_or_addr_select(bool sa) {
+  if(sa != current_bits.sa) {
+    _scroll_or_addr_select(sa);
+  }
+}
+
+void ST7920_Lite_Status_Screen::set_ddram_address(uint8_t addr) {
+  extended_function_set(false);
+  cmd(0b10000000 | (addr & 0b00111111));
+}
+
+void ST7920_Lite_Status_Screen::set_cgram_address(uint8_t addr) {
+  extended_function_set(false);
+  cmd(0b01000000 | (addr & 0b00111111));
+}
+
+void ST7920_Lite_Status_Screen::set_gdram_address(uint8_t x, uint8_t y) {
+  extended_function_set(true);
+  cmd(0b10000000 | (y & 0b01111111));
+  cmd(0b10000000 | (x & 0b00001111));
+}
+
+void ST7920_Lite_Status_Screen::clear() {
+  extended_function_set(false);
+  cmd(0x00000001);
+  delay(15);                 //delay for CGRAM clear
+}
+
+void ST7920_Lite_Status_Screen::home() {
+  extended_function_set(false);
+  cmd(0x00000010);
+}
+
+/* This fills the entire text buffer with spaces */
+void ST7920_Lite_Status_Screen::clear_ddram()
+{
+  set_ddram_address(DDRAM_LINE_1);
+  begin_data();
+  for(int i=0; i < 64;i++) {
+    write_byte(' ');
+  }
+}
+
+/* This fills the entire graphics buffer with zeros */
+void ST7920_Lite_Status_Screen::clear_gdram()
+{
+  for(int y = 0; y < BUFFER_HEIGHT; y++) {
+    set_gdram_address(0,y);
+    begin_data();
+    for(int i = 0; i < (BUFFER_WIDTH / 16); i++) {
+      write_byte(0);
+      write_byte(0);
+    }
+  }
+}
+
+void ST7920_Lite_Status_Screen::load_cgram_icon(uint16_t addr, const void *data) {
+  const uint16_t *p_word = (const uint16_t *)data;
+  set_cgram_address(addr);
+  begin_data();
+  for(int i = 0; i < 16; i++) {
+    uint16_t word = pgm_read_word_near(p_word++);
+    write_byte((word & 0xFF00) >> 8);
+    write_byte((word & 0x00FF) >> 0);
+  }
+}
+
+/* Draws an icon in GDRAM. The position is specified in
+   as if they were DDRAM coordinates, i.e. the x position
+   is [1-8], while the y position is [1-4] */
+void ST7920_Lite_Status_Screen::draw_gdram_icon(uint8_t x, uint8_t y, const void *data) {
+  const uint16_t *p_word = (const uint16_t *)data;
+  if(y > 2) {
+    // Handle display folding
+    y -= 2;
+    x += 8;
+  }
+  x -= 1;
+  y -= 1;
+  for(int i = 0; i < 16; i++) {
+    uint16_t word = pgm_read_word_near(p_word++);
+    set_gdram_address(x,i+y*16);
+    begin_data();
+    write_byte((word & 0xFF00) >> 8);
+    write_byte((word & 0x00FF) >> 0);
+  }
+}
+
+/************************** MAIN SCREEN *************************************/
+
+void ST7920_Lite_Status_Screen::draw_static_elements() {
+  scroll_or_addr_select(0);
+
+  // Load the animated bed and fan icons
+  load_cgram_icon(CGRAM_ICON_1_ADDR, heat1_icon);
+  load_cgram_icon(CGRAM_ICON_2_ADDR, heat2_icon);
+  load_cgram_icon(CGRAM_ICON_3_ADDR, fan1_icon);
+  load_cgram_icon(CGRAM_ICON_4_ADDR, fan2_icon);
+
+  // Draw the static icons in GDRAM
+  draw_gdram_icon(1,1,nozzle_icon);
+  #if EXTRUDERS == 2
+  draw_gdram_icon(1,2,nozzle_icon);
+  #endif
+  draw_gdram_icon(6,2,feedrate_icon);
+  draw_gdram_icon(1,2,bed_icon);
+
+  // Draw the initial fan icon
+  draw_fan_icon(false);
+}
+
+/* Although this is undocumented, the ST7920 allows the character
+ * data buffer (DDRAM) to be used in conjunction with the graphics
+ * bitmap buffer (CGRAM). The contents of the graphics buffer is
+ * XORed with the data from the character generator. This allows
+ * us to make the progess bar out of graphical data (the bar) and
+ * text data (the percentage).
+ */
+void ST7920_Lite_Status_Screen::draw_progress_bar(uint8_t value) {
+  #if EXTRUDERS == 1
+    // If we have only one extruder, draw a long progress bar on the third line
+    const int top        = 1;         // Top in pixels
+    const int bottom     = 13;        // Bottom in pixels
+    const int left       = 8;         // Left edge, in 16-bit words
+    const int width      = 5;         // Width of progress bar, in 16-bit words
+  #else
+    const int top        = 16 + 1;    // Top in pixels
+    const int bottom     = 16 + 13;   // Bottom in pixels
+    const int left       = 5;         // Left edge, in 16-bit words
+    const int width      = 3;         // Width of progress bar, in 16-bit words
+  #endif
+  const int char_pcnt  = 100/width; // How many percent does each 16-bit word represent?
+
+  // Draw the progress bar as a bitmap in CGRAM
+
+  for(int y = top; y <= bottom; y++) {
+    set_gdram_address(left,y);
+    begin_data();
+    for(int x = 0; x < width; x++) {
+      uint16_t gfx_word = 0x0000;
+      if((x+1)*char_pcnt <= value) {
+        // Draw completely filled bytes
+        gfx_word = 0xFFFF;
+      } else if((x*char_pcnt) < value) {
+        // Draw partially filled bytes
+        gfx_word = int(0x8000) >> (value % char_pcnt)*16/char_pcnt;
+      }
+      // Draw the frame around the progress bar
+      if(y == top || y == bottom) {
+        // Draw top/bottom border
+        gfx_word = 0xFFFF;
+      } else if (x == (width-1)) {
+        // Draw right border
+        gfx_word |= 0x0001;
+      } else if (x == 0) {
+        // Draw left border
+        gfx_word |= 0x8000;
+      }
+      write_word(gfx_word);
+    }
+  }
+
+  // Draw the percentage as text in DDRAM
+
+  #if EXTRUDERS == 1
+    set_ddram_address(DDRAM_LINE_3 + 1);
+  #else
+    set_ddram_address(DDRAM_LINE_2 + left);
+  #endif
+
+  begin_data();
+  if(value > 9) {
+    write_number(value,4);
+    write_str(F("% "));
+  } else {
+    write_number(value,3);
+    write_str(F("%  "));
+  }
+}
+
+void ST7920_Lite_Status_Screen::draw_fan_icon(bool whichIcon) {
+  set_ddram_address(DDRAM_LINE_1+5);
+  begin_data();
+  write_word(whichIcon ? CGRAM_ICON_3_WORD : CGRAM_ICON_4_WORD);
+}
+
+void ST7920_Lite_Status_Screen::draw_heat_icon(bool whichIcon, bool heating) {
+  #if EXTRUDERS == 1
+    set_ddram_address(DDRAM_LINE_2);
+  #else
+    set_ddram_address(DDRAM_LINE_3);
+  #endif
+  begin_data();
+  if(heating) {
+    write_word(whichIcon ? CGRAM_ICON_1_WORD : CGRAM_ICON_2_WORD);
+  } else {
+    write_byte(' ');
+    write_byte(' ');
+  }
+}
+
+#define FAR(a,b) (((a > b) ? (a-b) : (b-a)) > 1)
+
+void ST7920_Lite_Status_Screen::draw_extruder_1_temp(uint8_t temp, uint8_t target) {
+  set_ddram_address(DDRAM_LINE_1+1);
+  begin_data();
+  write_number(temp);
+  if(target && FAR(temp, target)) {
+    write_str(F("\x1A"));
+    write_number(target);
+  } else {
+    write_str(F("    "));
+  }
+}
+
+void ST7920_Lite_Status_Screen::draw_extruder_2_temp(uint8_t temp, uint8_t target) {
+  set_ddram_address(DDRAM_LINE_2+1);
+  begin_data();
+  write_number(temp);
+  if(target && FAR(temp, target)) {
+    write_str(F("\x1A"));
+    write_number(target);
+  } else {
+    write_str(F("    "));
+  }
+}
+
+void ST7920_Lite_Status_Screen::draw_bed_temp(uint8_t temp, uint8_t target) {
+  #if EXTRUDERS == 1
+  set_ddram_address(DDRAM_LINE_2+1);
+  #else
+  set_ddram_address(DDRAM_LINE_3+1);
+  #endif
+  begin_data();
+  write_number(temp);
+  if(target && FAR(temp, target)) {
+    write_str(F("\x1A"));
+    write_number(target);
+  } else {
+    write_str(F("    "));
+  }
+}
+
+void ST7920_Lite_Status_Screen::draw_fan_speed(uint8_t value) {
+  set_ddram_address(DDRAM_LINE_1+6);
+  begin_data();
+  write_number(value,4);
+}
+
+void ST7920_Lite_Status_Screen::draw_print_time(uint32_t elapsed) {
+  const uint8_t hrs = elapsed/3600;
+  const uint8_t min = (elapsed/60)%60;
+  char  str[7];
+  sprintf_P(str,hrs > 99 ? PSTR("%03d:%02d") : PSTR(" %02d:%02d"),hrs,min);
+
+  set_ddram_address(DDRAM_LINE_3+5);
+  begin_data();
+  write_str(str);
+}
+
+void ST7920_Lite_Status_Screen::draw_feedrate_percentage(uint8_t percentage) {
+  // We only have enough room for the feedrate when
+  // we have one extruder
+  #if EXTRUDERS == 1
+    set_ddram_address(DDRAM_LINE_2+6);
+    begin_data();
+    write_number(percentage,4);
+  #endif
+}
+
+void ST7920_Lite_Status_Screen::draw_status_message(const unsigned char *str) {
+  set_ddram_address(DDRAM_LINE_4);
+  begin_data();
+  #if ENABLED(STATUS_MESSAGE_SCROLLING)
+    const uint8_t lcd_len = 16;
+    const uint8_t padding = 2;
+    uint8_t str_len = strlen(str);
+
+    // Trim whitespace at the end of the str, as for some reason
+    // messages like "Card Inserted" are padded with many spaces
+    while(str_len > 0 && str[str_len-1] == ' ') {
+      str_len--;
+    }
+
+    if(str_len <= lcd_len) {
+      // It all fits on the LCD without scrolling
+      write_str(str);
+    } else {
+      // Print the message repeatedly until covering the LCD
+      uint8_t c = status_scroll_pos;
+      for(uint8_t n = 0; n < lcd_len; n++) {
+        write_byte(c < str_len ? str[c] : ' ');
+        c++;
+        c %= str_len + padding; // Wrap around
+      }
+
+      // Scroll the message
+      if(status_scroll_pos == str_len + padding) {
+        status_scroll_pos = 0;
+      } else {
+        status_scroll_pos++;
+      }
+    }
+  #else
+    write_str(str, 16);
+  #endif
+}
+
+void ST7920_Lite_Status_Screen::draw_position(const float x, const float y, const float z, bool position_known) {
+  char str[7];
+  set_ddram_address(DDRAM_LINE_4);
+  begin_data();
+
+  // If position is unknown, flash the labels.
+  const unsigned char alt_label = position_known ? 0 : (lcd_blink() ? ' ' : 0);
+
+  dtostrf(x, -4, 0, str);
+  write_byte(alt_label ? alt_label : 'X');
+  write_str(str, 4);
+
+  dtostrf(y, -4, 0, str);
+  write_byte(alt_label ? alt_label : 'Y');
+  write_str(str, 4);
+
+  dtostrf(z, -5, 1, str);
+  write_byte(alt_label ? alt_label : 'Z');
+  write_str(str, 5);
+}
+
+bool ST7920_Lite_Status_Screen::indicators_changed() {
+  // We only add the target temperatures to the checksum
+  // because the actual temps fluctuate so by updating
+  // them only during blinks we gain a bit of stability.
+  const bool       blink             = lcd_blink();
+  const uint8_t    feedrate_perc     = feedrate_percentage;
+  const uint8_t    fan_speed         = ((fanSpeeds[0] + 1) * 100) / 256;
+  const float      extruder_1_target = thermalManager.degTargetHotend(0);
+  #if EXTRUDERS == 2
+  const float      extruder_2_target = thermalManager.degTargetHotend(1);
+  #endif
+  const float      bed_target        = thermalManager.degTargetBed();
+
+  static uint8_t last_checksum = 0;
+
+  const  uint8_t checksum =
+    uint8_t(blink) ^
+    uint8_t(feedrate_perc) ^
+    uint8_t(fan_speed) ^
+    uint8_t(extruder_1_target) ^
+#if EXTRUDERS == 2
+    uint8_t(extruder_2_target) ^
+#endif
+    uint8_t(bed_target);
+
+  if(last_checksum == checksum) {
+    return false;
+  } else {
+    last_checksum = checksum;
+    return true;
+  }
+}
+
+void ST7920_Lite_Status_Screen::update_indicators(bool forceUpdate) {
+  if(forceUpdate || indicators_changed()) {
+    const bool       blink             = lcd_blink();
+    const duration_t elapsed           = print_job_timer.duration();
+    const uint32_t   seconds_elapsed   = elapsed.value;
+    const uint8_t    feedrate_perc     = feedrate_percentage;
+    const uint8_t    fan_speed         = ((fanSpeeds[0] + 1) * 100) / 256;
+    const float      extruder_1_temp   = thermalManager.degHotend(0);
+    const float      extruder_1_target = thermalManager.degTargetHotend(0);
+    #if EXTRUDERS == 2
+    const float      extruder_2_temp   = thermalManager.degHotend(1);
+    const float      extruder_2_target = thermalManager.degTargetHotend(1);
+    #endif
+    const float      bed_temp          = thermalManager.degBed();
+    const float      bed_target        = thermalManager.degTargetBed();
+
+    draw_extruder_1_temp(extruder_1_temp, extruder_1_target);
+    #if EXTRUDERS == 2
+    draw_extruder_2_temp(extruder_2_temp, extruder_2_target);
+    #endif
+    draw_bed_temp(bed_temp, bed_target);
+    draw_fan_speed(fan_speed);
+    draw_print_time(seconds_elapsed);
+    draw_feedrate_percentage(feedrate_perc);
+
+    // Update the fan and bed animations
+    if(fan_speed > 0) {
+      draw_fan_icon(blink);
+    }
+    if(bed_target > 0) {
+      draw_heat_icon(blink, true);
+    } else {
+      draw_heat_icon(false, false);
+    }
+  }
+}
+
+bool ST7920_Lite_Status_Screen::position_changed() {
+  const float x_pos = current_position[X_AXIS];
+  const float y_pos = current_position[Y_AXIS];
+  const float z_pos = current_position[Z_AXIS];
+  const uint8_t checksum = uint8_t(x_pos) ^ uint8_t(y_pos) ^ uint8_t(z_pos);
+
+  static uint8_t last_checksum = 0;
+  if(last_checksum == checksum) {
+    return false;
+  } else {
+    last_checksum = checksum;
+    return true;
+  }
+}
+
+bool ST7920_Lite_Status_Screen::status_changed() {
+  uint8_t checksum = 0;
+  for(const char *p = lcd_status_message; *p; p++) {
+    checksum ^= *p;
+  }
+
+  static uint8_t last_checksum = 0;
+  if(last_checksum == checksum) {
+    return false;
+  } else {
+    last_checksum = checksum;
+    return true;
+  }
+}
+
+bool ST7920_Lite_Status_Screen::blink_changed() {
+  static uint8_t last_blink = 0;
+
+  const bool blink = lcd_blink();
+  if(last_blink == blink) {
+    return false;
+  } else {
+    last_blink = blink;
+    return true;
+  }
+}
+
+void ST7920_Lite_Status_Screen::update_status_or_position(bool forceUpdate) {
+  static uint8_t countdown = 0;
+
+  /* There is only enough room in the display for either the
+   * status message or the position, not both, so we choose
+   * one or another. Whenever the status message changes,
+   * we show it for a number of consecutive seconds, but
+   * then go back to showing the position as soon as the
+   * head moves, i.e:
+   *
+   *    countdown > 1    -- Show status
+   *    countdown = 1    -- Show status, until movement
+   *    countdown = 0    -- Show position
+   */
+  if( forceUpdate || status_changed() ) {
+    #if ENABLED(STATUS_MESSAGE_SCROLLING)
+      status_scroll_pos = 0;
+    #endif
+    if(lcd_strlen(lcd_status_message)) {
+      countdown = DELAY_TO_SHOW_POSITION;
+    } else {
+      countdown = 0;
+    }
+    draw_status_message(lcd_status_message);
+    blink_changed(); // Clear changed flag
+  }
+  else if(countdown > 1 && blink_changed() ) {
+    countdown--;
+    #if ENABLED(STATUS_MESSAGE_SCROLLING)
+    draw_status_message(lcd_status_message);
+    #endif
+  }
+  else if(countdown > 0 && blink_changed() ) {
+    if(position_changed()) {
+      countdown--;
+      forceUpdate = true;
+    }
+    #if ENABLED(STATUS_MESSAGE_SCROLLING)
+    draw_status_message(lcd_status_message);
+    #endif
+  }
+  if(countdown == 0 && (forceUpdate || position_changed() ||
+    #if DISABLED(DISABLE_REDUCED_ACCURACY_WARNING)
+    blink_changed()
+    #endif
+  )) {
+    draw_position(
+      current_position[X_AXIS],
+      current_position[Y_AXIS],
+      current_position[Z_AXIS],
+      #if ENABLED(DISABLE_REDUCED_ACCURACY_WARNING)
+        true
+      #else
+        axis_known_position[X_AXIS] &&
+        axis_known_position[Y_AXIS] &&
+        axis_known_position[Z_AXIS]
+      #endif
+    );
+  }
+}
+
+void ST7920_Lite_Status_Screen::update_progress(bool forceUpdate) {
+  #if ENABLED(SDSUPPORT)
+    const uint8_t percent_done = card.percentDone();
+  #else
+    const uint8_t percent_done = 0;
+  #endif
+
+  // Since the progress bar involves writing
+  // quite a few bytes to GDRAM, only do this
+  // when an update is actually necessary.
+
+  static uint8_t last_progress = 0;
+  if(!forceUpdate && last_progress == percent_done)
+    return;
+  last_progress = percent_done;
+
+  draw_progress_bar(percent_done);
+}
+
+void ST7920_Lite_Status_Screen::update(bool forceUpdate) {
+  cs();
+  update_indicators(forceUpdate);
+  update_status_or_position(forceUpdate);
+  update_progress(forceUpdate);
+  ncs();
+}
+
+void ST7920_Lite_Status_Screen::reset_state_from_unknown() {
+  _extended_function_set(true, true); // Do it twice as only one bit
+  _extended_function_set(true, true); // get set at a time.
+  _scroll_or_addr_select(false);
+}
+
+void ST7920_Lite_Status_Screen::on_entry() {
+  cs();
+  reset_state_from_unknown();
+  clear();
+  clear_gdram();
+  draw_static_elements();
+  update(true);
+  ncs();
+}
+
+void ST7920_Lite_Status_Screen::on_exit() {
+  cs();
+  clear();
+  _extended_function_set(true, true); // Restore state to what u8g expects.
+  ncs();
+}
+
+// This is called prior to the KILL screen to
+// clear the screen so we don't end up with a
+// garbled display.
+void ST7920_Lite_Status_Screen::clear_text_buffer() {
+  cs();
+  reset_state_from_unknown();
+  clear();
+  _extended_function_set(true, true); // Restore state to what u8g expects.
+  ncs();
+}
+
+static void lcd_implementation_status_screen() {
+  ST7920_Lite_Status_Screen::update(false);
+}
+
+/* In order to properly update the lite status screen,
+ * we must know when we have entered and left the
+ * status screen. Since the ultralcd code is not
+ * set up for doing this, we call this function before
+ * each update indicating whether the current screen
+ * is the status screen.
+ *
+ * This function keeps track of whether we have left or
+ * entered the status screen and calls the on_entry()
+ * and on_exit() methods for cleanup.
+ */
+
+static void lcd_in_status(bool inStatus) {
+  static bool lastInStatus = false;
+  if(!lastInStatus && inStatus) {
+    ST7920_Lite_Status_Screen::on_entry();
+    lastInStatus = true;
+  }
+  if(lastInStatus && !inStatus) {
+    ST7920_Lite_Status_Screen::on_exit();
+    lastInStatus = false;
+  }
+}

Marlin/src/lcd/dogm/ultralcd_impl_st7920_lite_status_screen_impl_spi.h

@@ -0,0 +1,39 @@
+/*
+ * Lightweight Status Screen for the RepRapDiscount Full
+ * Graphics Smart Controller (ST7920-based 128x64 LCD)
+ *
+ * (c) 2017 Aleph Objects, Inc.
+ *
+ * The code in this page is free software: you can
+ * redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GNU GPL) as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option)
+ * any later version.  The code is distributed WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU GPL for more details.
+ *
+ */
+
+#include "ultralcd_impl_st7920_lite_status_screen.h"
+
+void ST7920_Lite_Status_Screen::cs() {
+  ST7920_CS();
+  current_bits.synced = false;
+}
+
+void ST7920_Lite_Status_Screen::ncs() {
+  ST7920_NCS();
+  current_bits.synced = false;
+}
+
+void ST7920_Lite_Status_Screen::sync_cmd() {
+  ST7920_SET_CMD();
+}
+
+void ST7920_Lite_Status_Screen::sync_dat() {
+  ST7920_SET_DAT();
+}
+
+void ST7920_Lite_Status_Screen::write_byte(uint8_t data) {
+  ST7920_WRITE_NIBBLES(data);
+}