mirror of
https://github.com/torvalds/linux
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96 lines
2.3 KiB
C
96 lines
2.3 KiB
C
/*
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* lcd44780.c
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* Simple "driver" for a memory-mapped 44780-style LCD display.
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*
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* Copyright 2001 Bradley D. LaRonde <brad@ltc.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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*/
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#define LCD44780_COMMAND ((volatile unsigned char *)0xbe020000)
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#define LCD44780_DATA ((volatile unsigned char *)0xbe020001)
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#define LCD44780_4BIT_1LINE 0x20
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#define LCD44780_4BIT_2LINE 0x28
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#define LCD44780_8BIT_1LINE 0x30
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#define LCD44780_8BIT_2LINE 0x38
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#define LCD44780_MODE_DEC 0x04
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#define LCD44780_MODE_DEC_SHIFT 0x05
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#define LCD44780_MODE_INC 0x06
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#define LCD44780_MODE_INC_SHIFT 0x07
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#define LCD44780_SCROLL_LEFT 0x18
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#define LCD44780_SCROLL_RIGHT 0x1e
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#define LCD44780_CURSOR_UNDERLINE 0x0e
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#define LCD44780_CURSOR_BLOCK 0x0f
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#define LCD44780_CURSOR_OFF 0x0c
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#define LCD44780_CLEAR 0x01
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#define LCD44780_BLANK 0x08
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#define LCD44780_RESTORE 0x0c // Same as CURSOR_OFF
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#define LCD44780_HOME 0x02
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#define LCD44780_LEFT 0x10
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#define LCD44780_RIGHT 0x14
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void lcd44780_wait(void)
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{
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int i, j;
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for(i=0; i < 400; i++)
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for(j=0; j < 10000; j++);
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}
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void lcd44780_command(unsigned char c)
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{
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*LCD44780_COMMAND = c;
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lcd44780_wait();
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}
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void lcd44780_data(unsigned char c)
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{
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*LCD44780_DATA = c;
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lcd44780_wait();
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}
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void lcd44780_puts(const char* s)
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{
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int j;
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int pos = 0;
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lcd44780_command(LCD44780_CLEAR);
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while(*s) {
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lcd44780_data(*s);
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s++;
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pos++;
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if (pos == 8) {
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/* We must write 32 of spaces to get cursor to 2nd line */
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for (j=0; j<32; j++) {
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lcd44780_data(' ');
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}
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}
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if (pos == 16) {
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/* We have filled all 16 character positions, so stop
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outputing data */
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break;
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}
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}
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#ifdef LCD44780_PUTS_PAUSE
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{
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int i;
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for(i = 1; i < 2000; i++)
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lcd44780_wait();
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}
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#endif
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}
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void lcd44780_init(void)
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{
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// The display on the RockHopper is physically a single
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// 16 char line (two 8 char lines concatenated). bdl
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lcd44780_command(LCD44780_8BIT_2LINE);
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lcd44780_command(LCD44780_MODE_INC);
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lcd44780_command(LCD44780_CURSOR_BLOCK);
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lcd44780_command(LCD44780_CLEAR);
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}
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