Author: robhamerling
Date: Tue Oct 14 08:34:58 2008
New Revision: 408
Modified:
trunk/unvalidated/include/external/lcd/lcd_hd44780_4.jal
Log:
renamed lcd_setup() to lcd_init(), updated and reformatted comments for
jalapi processing
Modified: trunk/unvalidated/include/external/lcd/lcd_hd44780_4.jal
==============================================================================
--- trunk/unvalidated/include/external/lcd/lcd_hd44780_4.jal (original)
+++ trunk/unvalidated/include/external/lcd/lcd_hd44780_4.jal Tue Oct 14
08:34:58 2008
@@ -20,25 +20,25 @@
--
-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
--
--- Directions for use of this library:
+-- Directions for use of this library in application programs
+-- (in this sequence):
--
--- The application program must declare the following variables (aliases)
--- and constants _before_ the include of this library:
+-- 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 byte lcd_dataport is portA_low -- 4 data pins
+-- var bit lcd_en is pin_A4 -- trigger
+-- var bit lcd_rs is pin_A5 -- cmd/data select
+--
+-- 2. Include this library.
+--
+-- 3. Set the LCD dataport and handshake pins to output:
+-- portA_low_direction = all_output
+-- pin_A4_direction = output
+-- pin_A5_direction = output
--
--- const byte LCD_ROWS = 2 -- 2 lines
--- const byte LCD_CHARS = 16 -- 16 chars per line
---
--- var byte lcd_dataport is portA_low -- LCD data
--- var bit lcd_en is pin_A4 -- LCD data trigger
--- var bit lcd_rs is pin_A5 -- LCD cmd/data select
---
--- Then set the dataport and handshake pin directions:
---
--- PortA_low_direction = all_output -- make datapath output
--- pin_A4_direction = output -- \
--- pin_A5_direction = output -- / make handshake lines
output
---
--- And then include this library.
+-- 4. Call lcd_init() to initialize the lcd controller.
--
-- Above is an example for a 2x16 LCD.
-- Bits 0..3 of portA are used for data, pins 4 and 5 of portA are
@@ -46,21 +46,22 @@
-- could be used (provided these are configurable for output).
--
-- Available functions for application programs:
--- lcd_setup() (called automatically)
--- lcd_clearscreen() clear screen, cursor
home
--- lcd_setcursor(<row>,<column>) where to write next
character
--- lcd_writechar(<byte>) write single character
--- at cursor position and
--- shift cursor position 1
right
+--
+-- lcd_init() initialize the LCD
controller
+-- lcd_clearscreen() clear screen, cursor home
+-- lcd_setcursor(<row>,<column>) where to write next
character
+-- lcd_writechar(<byte>) write single character
+-- at cursor position and
+-- shift cursor position 1
right
--
-- A pseudo byte variable 'lcd' is declared as alternative for
lcd_writechar(<byte>)
--- So in stead of writing: lcd_writechar(<byte>)
--- you may write: lcd = <byte>
+-- So in stead of: lcd_writechar(<byte>)
+-- you may use: lcd = <byte>
-- And you may use 'lcd' as destination in other functions, like print().
--
--- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+--
-----------------------------------------------------------------------------
-include delay_any_mc -- delay procedures
+include delay_any_mc -- standard delay
procedures
-- -----------------------------------------------------
-- Write nibble (lower order 4 bits of byte) to LCD.
@@ -69,7 +70,6 @@
-- When wait is required after write then caller should wait
-- (in 4-bit mode only required after second nibble).
-- -----------------------------------------------------
-
procedure _lcd_writenibble(byte in data) is
lcd_dataport = data -- replace low nibble
@@ -84,7 +84,6 @@
-- and automatically set the cursor one position right.
-- There is no check on line overflow.
-- ----------------------------------------------------------
-
procedure lcd_writechar(byte in c) is
_lcd_writenibble(c >> 4) -- write high nibble
@@ -97,7 +96,6 @@
-- ----------------------------------------------------------
-- Pseudo variable 'lcd' as alternative for lcd_writechar(<byte>)
-- ----------------------------------------------------------
-
procedure lcd'put(byte in c) is
lcd_writechar(c)
end procedure
@@ -107,7 +105,6 @@
-- Clear screen
-- (and set the cursor to the upper left corner: row 0, column 0)
-- ------------------------------------------------------------
-
procedure lcd_clearscreen() is
lcd_rs = LOW -- set to control char mode
@@ -122,24 +119,22 @@
-- The first line starts at offset 0, the second line at offset 64 (0x40).
-- With 4 line devices the third and fourth line are addressed as
extensions
-- of the first and second line by adding an offset. For a 4x20 line device
--- the offset is 20, for a 4x16 line display the offset is 16 or 20
+-- the offset is 20, for a 4x16 line display the offset is 16 or 20.
-- Declare the constant LCD_CHARS as appropriate for your screen
-- (you may have to specify 20 even if your display has only 16 chars!).
-- Note: Some 1x16 LCDs are implemented as 2x8 line LCDs, which means that
--- the second half of the line has to be handled as the second line.
---
+-- the second half of the line has to be handled as a second line.
-- ------------------------------------------------------------
-- Set cursor position
-- Specify row and column in base-0 notation (first line is 0).
-- ------------------------------------------------------------
-
procedure lcd_setcursor(byte in row, byte in col) is
col = col | 0b1000_0000 -- set to DRAM offset top
line
case row of
1: col = col + 0x40 -- 2nd line of 2 or 4 line
lcd
- 2: col = col + LCD_CHARS -- 3rd line \ 4x16 or
- 3: col = col + 0x40 + LCD_CHARS -- 4th line / 4x20
+ 2: col = col + LCD_CHARS -- 3rd line \ with 4x16
+ 3: col = col + 0x40 + LCD_CHARS -- 4th line / or 4x20
end case
lcd_rs = LOW -- set to control char mode
lcd_writechar(col) -- set new cursor position
@@ -154,8 +149,7 @@
-- - 2-line (/ 4-line) mode
-- - shift right, invisible cursor
-- -----------------------------------------------------
-
-procedure lcd_setup() is
+procedure lcd_init() is
lcd_rs = LOW -- set to control char mode
delay_1ms(25) -- power-up delay (> 15 ms)
@@ -175,12 +169,4 @@
-- (incl switch to data
char mode)
end procedure
-
--- -----------------------------------------------------
--- actually initialize the LCD
--- -----------------------------------------------------
-
-lcd_setup() -- to get the LCD active
-
--- -----------------------------------------------------
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