# lcd_dog_m_spi

control for DOG-M (ST7036 based) LCD's

Author | Richard Zengerink, Copyright © 2008, all rights reserved
Adapted-by |
Compiler | =2.4

Description

       Simple interface for DOG-M (st7036) alphanumeric LCD screens.
       Screens can range from 1x8  (1 lines, 8 chars), 2x16 and 3x16.
       Uses spi interface SI (data line), CLK (clock) RS (register select) and
       if necesery CSB (chip select) (total 4 PIC pins max.).
       Expects: - 1 pin for data: 'lcd_data'
                - 1 pin for clock: 'lcd_clk'
                - 1 pin for register/data select: 'lcd_rs'
                - 1 pin for Chip Select 'lcd_csb'  (if necesery, or CSB to gnd on lcd)
                - 1 var bit named not_connected to assign to lcd_csb if this pin
                  is connected to ground.
       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 3 lines
             const byte LCD_CHARS    = 16             -- 8, or 16 chars per line
          and variables (aliases):
             var   bit not_connected
             var   bit  lcd_data      is  pin_A0      -- 1 data pin
             var   bit  lcd_clk       is  pin_A1      -- 1 data pin
             var   bit  lcd_rs        is  pin_A2      -- 1 data pin
             var   bit  lcd_csb       is  pin_A3      -- 1 data pin
         or if csb is connected to gnd:
             var   bit  lcd_csb       is  not_connected
    .
       2. Include this library.
       and somewhere before actually using the lcd:
       3. Set the chosen LCD data and control pins to output:
             portA_low_direction = all_output  (in above case this is OK)
        OR assign each pin seperatly (when not every pin is on the same port):
             pin_A0_direction    = output      (each pin separately assigned)
             pin_A1_direction    = output
             pin_b0_direction    = output
             pin_b1_direction    = output
       4. Call lcd_init() to initialize the lcd controller.
       Above is an example for a 2x16 LCD:
    .
       Available functions for application programs:
    .
         _lcd_write()                     ends byte from value to
                                                register of the lcd  and
                                                shift cursor position 1 right
    .
         _lcd_write_data()                write data to lcd using
                                                _lcd_write() lcd_rs high
    .
         _lcd_write_data()                write command to lcd using
                                                _lcd_write() lcd_rs low
    .
         lcd_init()                             initialize the LCD controller

Dependencies

- delay
- lcd_hd44780_common

## Summary

### Global variables/contants

- `const lcd_normal_delay = 3`
- `const lcd_long_delay = 120`

### Procedures

- `lcd_init()`

Private

- `_lcd_write(byte in value)`
- `_lcd_write_data(byte in value)`
- `_lcd_write_command(byte in value)`

### Functions

## API details

### Global variables/contants

- `const lcd_normal_delay = 3`

      delay's necessary for initialisation and some commands

- `const lcd_long_delay = 120`

      delay in 10 usec units     = 1,2mS

### Procedures

- `lcd_init()`

      Initialize display in 1 and 2 or 3 line, display on, no cursor shown an cursor
      moves to the right.

Private

- `_lcd_write(byte in value)`

      sends byte from value to register of the lcd
      (this procedure is only used inside this file)

- `_lcd_write_data(byte in value)`

      sends data byte in value to LCD
      for slow commands an extra delay should be added --

- `_lcd_write_command(byte in value)`

      sends command byte in value to LCD
      for slow commands an extra delay should be added

### Functions

## Related samples

No sample found