Author: jsuijs
Date: Sat Mar 7 07:53:18 2009
New Revision: 833
Added:
trunk/include/external/lcd/lcd_hd44780_serial_sw.jal
Log:
LCD display via serial software
Added: trunk/include/external/lcd/lcd_hd44780_serial_sw.jal
==============================================================================
--- (empty file)
+++ trunk/include/external/lcd/lcd_hd44780_serial_sw.jal Sat Mar 7
07:53:18 2009
@@ -0,0 +1,126 @@
+--
-----------------------------------------------------------------------------
+-- Title: LCD library for HD44780 compatible LCDs, interfaced with 1 pin
(serial_sw)
+-- Author: Joep Suijs, Copyright (c) 2008..2009, all rights reserved.
+-- Adapted-by:
+-- Compiler: >=2.4g
+--
+-- This file is part of jallib (http://jallib.googlecode.com)
+-- Released under the ZLIB license
(http://www.opensource.org/licenses/zlib-license.html)
+--
+-- Sources:
+--
+-- Description:
+-- Software serial interface for HD44780 compatible alphanumeric LCD
screens.
+-- --
+-- Directions for use of this library in application programs
+-- (in this sequence):
+-- 1. Declare the following constants:
+-- const byte LCD_ROWS = 2 -- 1, 2 or 4 lines
+-- const byte LCD_CHARS = 16 -- 8, 16 or 20 chars
per line
+-- and variables (aliases):
+-- var bit serial_sw_tx_pin is pin_d0 -- pin on which lcd
is connected
+-- --
+-- 2. Set the chosen LCD dataport and handshake pins to output:
+-- pin_d0_direction = output
+-- --
+-- 3. Include this library.
+-- --
+-- 4. Call lcd_init() to initialize the lcd controller.
+-- --
+-- Above is an example for a 2x16 LCD, connected to pin d0
+-- --
+-- See hd_44780_common for the LCD API.
+--
+-- Dependencies: delay.jal
+-- serial_software
+--
+--
-----------------------------------------------------------------------------
+
+include delay
+
+var bit serial_sw_rx_pin ; dummy to include lib; will be
optimised away.
+const bit serial_sw_invert = true ; normal (low active) serial
comms
+const serial_sw_baudrate = 57600
+include serial_software
+
+var bit lcd_rs_shadow
+
+--
----------------------------------------------------------------------------
+-- sends low nibble from value to the LCD
+-- can be used for both commands and data
+-- (requires no wait cycli inbetween upper and lower nibble)
+-- (this routine is only used inside this file)
+--
----------------------------------------------------------------------------
+procedure __lcd_write_nibble( byte in value ) is
+
+ value = value & 0x0F
+ if (lcd_rs_shadow) then
+ value = value | 0x10
+ end if
+
+ serial_sw_write(value) -- interrupts are disabled by lib
+end procedure
+--
----------------------------------------------------------------------------
+
+
+--
----------------------------------------------------------------------------
+-- sends byte from value to register of the LCD
+-- (this procedure is only used inside this file)
+--
+--
----------------------------------------------------------------------------
+procedure __lcd_write( byte in value ) is
+ __lcd_write_nibble(value >> 4) -- write high nibble
+ __lcd_write_nibble(value) -- write low nibble
+ ; delay of 37 us is not required, since each byte takes 170us to transer
+end procedure
+--
----------------------------------------------------------------------------
+
+
+--
----------------------------------------------------------------------------
+-- sends data byte in value to LCD
+-- for slow commands an extra delay should be added
+--
+--
----------------------------------------------------------------------------
+procedure _lcd_write_data(byte in value) is
+ lcd_rs_shadow = high -- select
instruction
+ __lcd_write( value ) -- output byte
+end procedure
+--
----------------------------------------------------------------------------
+
+
+--
----------------------------------------------------------------------------
+-- sends command byte in value to LCD
+-- for slow commands an extra delay should be added
+--
+--
----------------------------------------------------------------------------
+procedure _lcd_write_command(byte in value) is
+; pragma inline
+ lcd_rs_shadow = low -- select instruction
+ __lcd_write( value ) -- output byte
+end procedure
+--
----------------------------------------------------------------------------
+
+
+-- now we defined the interface, add the API
+include lcd_hd44780_common
+
+--
----------------------------------------------------------------------------
+--
----------------------------------------------------------------------------
+--
----------------------------------------------------------------------------
+procedure lcd_init() is
+
+ -- first, init the interface
+ lcd_rs_shadow = LOW -- set to control
char mode
+ delay_1ms(25) -- power-up delay (> 15 ms)
+ __lcd_write_nibble(0b0000_0011) -- function set
+ delay_1ms(5) -- > 4.1 milliseconds
+ __lcd_write_nibble(0b0000_0011) -- function set
+ delay_10us(10) -- > 100 us
+ __lcd_write_nibble(0b0000_0011) -- function set
+ delay_10us(4) -- > 37 us
+ __lcd_write_nibble(0b0000_0010) -- to 4-bit mode
+ delay_10us(4) -- > 37 us
+
+ -- init the API
+ _hd44780_init()
+end procedure
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