arch/mips/ddb5xxx/ddb5477/lcd44780.c

   1 /*
   2  * lcd44780.c
   3  * Simple "driver" for a memory-mapped 44780-style LCD display.
   4  *
   5  * Copyright 2001 Bradley D. LaRonde <brad@ltc.com>
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  *
  12  */
  13
  14 #define LCD44780_COMMAND   ((volatile unsigned char *)0xbe020000)
  15 #define LCD44780_DATA      ((volatile unsigned char *)0xbe020001)
  16
  17 #define LCD44780_4BIT_1LINE        0x20
  18 #define LCD44780_4BIT_2LINE        0x28
  19 #define LCD44780_8BIT_1LINE        0x30
  20 #define LCD44780_8BIT_2LINE        0x38
  21 #define LCD44780_MODE_DEC          0x04
  22 #define LCD44780_MODE_DEC_SHIFT    0x05
  23 #define LCD44780_MODE_INC          0x06
  24 #define LCD44780_MODE_INC_SHIFT    0x07
  25 #define LCD44780_SCROLL_LEFT       0x18
  26 #define LCD44780_SCROLL_RIGHT      0x1e
  27 #define LCD44780_CURSOR_UNDERLINE  0x0e
  28 #define LCD44780_CURSOR_BLOCK      0x0f
  29 #define LCD44780_CURSOR_OFF        0x0c
  30 #define LCD44780_CLEAR             0x01
  31 #define LCD44780_BLANK             0x08
  32 #define LCD44780_RESTORE           0x0c  // Same as CURSOR_OFF
  33 #define LCD44780_HOME              0x02
  34 #define LCD44780_LEFT              0x10
  35 #define LCD44780_RIGHT             0x14
  36
  37 void lcd44780_wait(void)
  38 {
  39         int i, j;
  40         for(i=0; i < 400; i++)
  41                 for(j=0; j < 10000; j++);
  42 }
  43
  44 void lcd44780_command(unsigned char c)
  45 {
  46         *LCD44780_COMMAND = c;
  47         lcd44780_wait();
  48 }
  49
  50 void lcd44780_data(unsigned char c)
  51 {
  52         *LCD44780_DATA = c;
  53         lcd44780_wait();
  54 }
  55
  56 void lcd44780_puts(const char* s)
  57 {
  58         int i,j;
  59         int pos = 0;
  60
  61         lcd44780_command(LCD44780_CLEAR);
  62         while(*s) {
  63                 lcd44780_data(*s);
  64                 s++;
  65                 pos++;
  66                 if (pos == 8) {
  67                   /* We must write 32 of spaces to get cursor to 2nd line */
  68                   for (j=0; j<32; j++) {
  69                     lcd44780_data(' ');
  70                   }
  71                 }
  72                 if (pos == 16) {
  73                   /* We have filled all 16 character positions, so stop
  74                      outputing data */
  75                   break;
  76                 }
  77         }
  78 #ifdef LCD44780_PUTS_PAUSE
  79         for(i = 1; i < 2000; i++)
  80                 lcd44780_wait();
  81 #endif
  82 }
  83
  84 void lcd44780_init(void)
  85 {
  86         // The display on the RockHopper is physically a single
  87         // 16 char line (two 8 char lines concatenated).  bdl
  88         lcd44780_command(LCD44780_8BIT_2LINE);
  89         lcd44780_command(LCD44780_MODE_INC);
  90         lcd44780_command(LCD44780_CURSOR_BLOCK);
  91         lcd44780_command(LCD44780_CLEAR);
  92 }