hd44780.c

嵌入式linux下液晶编程院代码, 可以在LINUX2.4内核下运行

}


static void HD_write (unsigned char controller, char *string, int len, int delay)
{
  unsigned char enable;

  if (Bits==8) {

    // enable signal: 'controller' is a bitmask
    // bit 0 .. send to controller #0
    // bit 1 .. send to controller #1
    // so we can send a byte to both controllers at the same time!
    enable=0;
    if (controller&0x01) enable|=SIGNAL_ENABLE;
    if (controller&0x02) enable|=SIGNAL_ENABLE2;
    
    // clear RW, set RS
    parport_control (SIGNAL_RW | SIGNAL_RS, SIGNAL_RS);

    // Address set-up time
    ndelay(T_AS);
    
    while (len--) {
      
      // put data on DB1..DB8
      parport_data (*(string++));
      
      // send command
      parport_toggle (enable, 1, T_PW);
      
      // wait for command completion
      udelay(delay);
    }
    
  } else { // 4 bit mode
    
    while (len--) {

      // send data with RS enabled
      HD_byte (controller, *(string++), SIGNAL_RS);
      
      // wait for command completion
      udelay(delay);
    }
  }
}


static void HD_setGPO (int bits)
{
  if (Lcd.gpos>0) {
    
    // put data on DB1..DB8
    parport_data (bits);
    
    // 74HCT573 set-up time
    ndelay(20);
    
    // send data
    // 74HCT573 enable pulse width = 24ns
    parport_toggle (SIGNAL_GPO, 1, 230);
  }
}


static void HD_define_char (int ascii, char *buffer)
{
  // define chars on *both* controllers!
  HD_command (0x03, 0x40|8*ascii, T_EXEC);
  HD_write (0x03, buffer, 8, T_WRCG);
}


int HD_clear (int full)
{

  memset (FrameBuffer1, ' ', Lcd.rows*Lcd.cols*sizeof(char));

  icon_clear();
  bar_clear();

  GPO=0;
  
  if (full) {
    memset (FrameBuffer2, ' ', Lcd.rows*Lcd.cols*sizeof(char));
    HD_command (0x03, 0x01, T_CLEAR); // clear *both* displays
    HD_command (0x03, 0x03, T_CLEAR); // return home
    HD_setGPO (GPO);                  // all GPO's off
  }
  
  return 0;
}


int HD_init (LCD *Self)
{
  int rows=-1, cols=-1, gpos=-1;
  char *s;
  
  s=cfg_get("Size",NULL);
  if (s==NULL || *s=='\0') {
    error ("HD44780: no 'Size' entry in %s", cfg_source());
    return -1;
  }
  if (sscanf(s,"%dx%d",&cols,&rows)!=2 || rows<1 || cols<1) {
    error ("HD44780: bad size '%s'",s);
    return -1;
  }
  
  if (cfg_number("GPOs", 0, 0, 8, &gpos)<0) return -1;
  info ("HD44780: controlling %d GPO's", gpos);

  if (cfg_number("Controllers", 1, 1, 2, &Controllers)<0) return -1;
  info ("wiring: using display with %d controllers", Controllers);
  
  // current controller
  Controller=1;
  
  Self->rows=rows;
  Self->cols=cols;
  Self->gpos=gpos;
  Lcd=*Self;
  
  // Init the framebuffers
  FrameBuffer1 = (char*)malloc(Lcd.cols*Lcd.rows*sizeof(char));
  FrameBuffer2 = (char*)malloc(Lcd.cols*Lcd.rows*sizeof(char));
  if (FrameBuffer1==NULL || FrameBuffer2==NULL) {
    error ("HD44780: framebuffer could not be allocated: malloc() failed");
    return -1;
  }
  
  if (cfg_number("Bits", 8, 4, 8, &Bits)<0) return -1;
  if (Bits!=4 && Bits!=8) {
    error ("HD44780: bad Bits '%s' in %s, should be '4' or '8'", s, cfg_source());
    return -1;
  }    
  info ("wiring: using %d bit mode", Bits);
  
  if (Bits==8) {
    if ((SIGNAL_RS      = parport_wire_ctrl ("RS",      "AUTOFD"))==0xff) return -1;
    if ((SIGNAL_RW      = parport_wire_ctrl ("RW",      "GND")   )==0xff) return -1;
    if ((SIGNAL_ENABLE  = parport_wire_ctrl ("ENABLE",  "STROBE"))==0xff) return -1;
    if ((SIGNAL_ENABLE2 = parport_wire_ctrl ("ENABLE2", "SELECT"))==0xff) return -1;
    if ((SIGNAL_GPO     = parport_wire_ctrl ("GPO",     "INIT")  )==0xff) return -1;
  } else {
    if ((SIGNAL_RS      = parport_wire_data ("RS",      "DB4"))==0xff) return -1;
    if ((SIGNAL_RW      = parport_wire_data ("RW",      "DB5"))==0xff) return -1;
    if ((SIGNAL_ENABLE  = parport_wire_data ("ENABLE",  "DB6"))==0xff) return -1;
    if ((SIGNAL_ENABLE2 = parport_wire_data ("ENABLE2", "DB7"))==0xff) return -1;
    if ((SIGNAL_GPO     = parport_wire_data ("GPO",     "GND"))==0xff) return -1;
  }
  
  if (parport_open() != 0) {
    error ("HD44780: could not initialize parallel port!");
    return -1;
  }

  // clear all signals
  if (Bits==8) {
    parport_control (SIGNAL_RS|SIGNAL_RW|SIGNAL_ENABLE|SIGNAL_ENABLE2|SIGNAL_GPO, 0);
  } else {
    parport_data (0);
  }

  // set direction: write
  parport_direction (0);

  // initialize *both* displays
  if (Bits==8) {
    HD_command (0x03, 0x30, T_INIT1); // 8 Bit mode, wait 4.1 ms
    HD_command (0x03, 0x30, T_INIT2); // 8 Bit mode, wait 100 us
    HD_command (0x03, 0x38, T_EXEC);  // 8 Bit mode, 1/16 duty cycle, 5x8 font
  } else {
    HD_nibble(0x03, 0x03); udelay(T_INIT1); // 4 Bit mode, wait 4.1 ms
    HD_nibble(0x03, 0x03); udelay(T_INIT2); // 4 Bit mode, wait 100 us
    HD_nibble(0x03, 0x03); udelay(T_INIT1); // 4 Bit mode, wait 4.1 ms
    HD_nibble(0x03, 0x02); udelay(T_INIT2); // 4 Bit mode, wait 100 us
    HD_command (0x03, 0x28, T_EXEC);	    // 4 Bit mode, 1/16 duty cycle, 5x8 font
  }
  
  HD_command (0x03, 0x08, T_EXEC);  // Display off, cursor off, blink off
  HD_command (0x03, 0x0c, T_CLEAR); // Display on, cursor off, blink off, wait 1.64 ms
  HD_command (0x03, 0x06, T_EXEC);  // curser moves to right, no shift

  if (cfg_number("Icons", 0, 0, CHARS, &Icons)<0) return -1;
  if (Icons>0) {
    debug ("reserving %d of %d user-defined characters for icons", Icons, CHARS);
    icon_init(Lcd.rows, Lcd.cols, XRES, YRES, CHARS, Icons, HD_define_char);
    Self->icons=Icons;
    Lcd.icons=Icons;
  }
  
  bar_init(rows, cols, XRES, YRES, CHARS-Icons);
  bar_add_segment(  0,  0,255, 32); // ASCII  32 = blank
  bar_add_segment(255,255,255,255); // ASCII 255 = block
  
  HD_clear(1);
  
  return 0;
}


void HD_goto (int row, int col)
{
  int pos;

  if (Controllers>1 && row>=2) {
    row -= 2;
    Controller = 2;
  } else {
    Controller = 1;
  }
   
  pos=(row%2)*64+(row/2)*20+col;
  HD_command (Controller, (0x80|pos), T_EXEC);
}


int HD_put (int row, int col, char *text)
{
  char *p=FrameBuffer1+row*Lcd.cols+col;
  char *t=text;
  
  while (*t && col++<=Lcd.cols) {
    *p++=*t++;
  }
  return 0;
}


int HD_bar (int type, int row, int col, int max, int len1, int len2)
{
  return bar_draw (type, row, col, max, len1, len2);
}


int HD_icon (int num, int seq, int row, int col)
{
  return icon_draw (num, seq, row, col);
}


int HD_gpo (int num, int val)
{
  if (num>=Lcd.gpos) 
    return -1;

  if (val) {
    GPO |= 1<<num;     // set bit
  } else {
    GPO &= ~(1<<num);  // clear bit
  }
  return 0;
}


int HD_flush (void)
{
  int row, col, pos1, pos2;
  int c, equal;
  
  bar_process(HD_define_char);

  for (row=0; row<Lcd.rows; row++) {
    for (col=0; col<Lcd.cols; col++) {
      c=bar_peek(row, col);
      if (c==-1) c=icon_peek(row, col);
      if (c!=-1) {
	FrameBuffer1[row*Lcd.cols+col]=(char)c;
      }
    }
    for (col=0; col<Lcd.cols; col++) {
      if (FrameBuffer1[row*Lcd.cols+col]==FrameBuffer2[row*Lcd.cols+col]) continue;
      HD_goto (row, col);
      for (pos1=col++, pos2=pos1, equal=0; col<Lcd.cols; col++) {
	if (FrameBuffer1[row*Lcd.cols+col]==FrameBuffer2[row*Lcd.cols+col]) {
	  // If we find just one equal byte, we don't break, because this 
	  // would require a goto, which takes one byte, too.
	  if (++equal>2) break;
	} else {
	  pos2=col;
	  equal=0;
	}
      }
      HD_write (Controller, FrameBuffer1+row*Lcd.cols+pos1, pos2-pos1+1, T_EXEC);
    }
  }

  memcpy (FrameBuffer2, FrameBuffer1, Lcd.rows*Lcd.cols*sizeof(char));

  HD_setGPO(GPO);

  return 0;
}


int HD_quit (void)
{
  info("HD44780: shutting down.");

  if (FrameBuffer1) {
    free(FrameBuffer1);
    FrameBuffer1=NULL;
  }

  if (FrameBuffer2) {
    free(FrameBuffer2);
    FrameBuffer2=NULL;
  }

  return parport_close();
}


LCD HD44780[] = {
  { name: "HD44780",
    rows:  0,
    cols:  0,
    xres:  XRES,
    yres:  YRES,
    bars:  BAR_L | BAR_R | BAR_U | BAR_D | BAR_H2,
    icons: 0,
    gpos:  0,
    init:  HD_init,
    clear: HD_clear,
    put:   HD_put,
    bar:   HD_bar,
    icon:  HD_icon,
    gpo:   HD_gpo,
    flush: HD_flush,
    quit:  HD_quit 
  },
  { NULL }
};