lcd_hd44780_4
LCD library for HD44780 compatible LCDs, with 4 bits wide datatransfer
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Author
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Rob Hamerling, Copyright © 2008..2009, all rights reserved.
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Adapted-by
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Eur van Andel, Joep Suijs (refactoring),Richard Zengerink (lcd_init)
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Compiler
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2.4p
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Description
Nibble interface for HD44780 compatible alphanumeric LCD screens.
Uses 4 bits wide datapath + 2 handshake lines (total 6 PIC pins).
Expects: 2 pins for handshake: 'lcd_rs' and 'lcd_en'
and
1 port nibble for data: 'lcd_dataport'
or
4 individual pins for data: 'lcd_d4' .. 'lcd_d7'
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Note: a 'port nibble' (the lower or higher 4 bits of a port)
gives faster and more compact code than 4 individual pins.
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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 aliases for handshake lines:
alias lcd_rs is pin_A5 -- cmd/data select
alias lcd_en is pin_A4 -- trigger
and aliases for 4 data lines:
alias lcd_dataport is portA_low -- 4 databits
or
alias lcd_d4 is pin_A3 -- lcd databit d4
alias lcd_d5 is pin_A1 -- lcd databit d5
alias lcd_d6 is pin_C0 -- lcd databit d6
alias lcd_d7 is pin_C2 -- lcd databit d7
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2. Set the chosen LCD dataport and handshake pins to output:
pin_A4_direction = output
pin_A5_direction = output
and the data port nibble to output:
portA_low_direction = all_output
or the 4 individual datapins to output:
pin_A3_direction = output
pin_A1_direction = output
pin_C0_direction = output
pin_C2_direction = output
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3. Include this library.
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4. Call lcd_init() to initialize the lcd controller.
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Above is an example for a 2x16 LCD.
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See hd_44780_common for the LCD API.
Dependencies
Private
Private
Here are the list of samples which use this library: