raspberrypi/st7565-lcd/raspilcd.adb

with Interfaces;
use Interfaces;
with Interfaces.C;
use Interfaces.C;
with Interfaces.C.extensions;
use Interfaces.C.extensions;
with bcm2835_h;
use bcm2835_h;



package body RaspiLcd is


    procedure io_init is
    begin
        bcm2835_gpio_fsel(pin => LCD_CS, mode => unsigned_char(BCM2835_GPIO_FSEL_OUTP));
        bcm2835_gpio_fsel(pin => LCD_RST, mode => unsigned_char(BCM2835_GPIO_FSEL_OUTP));
        bcm2835_gpio_fsel(pin => LCD_A0, mode => unsigned_char(BCM2835_GPIO_FSEL_OUTP));
        bcm2835_gpio_fsel(pin => LCD_CLK, mode => unsigned_char(BCM2835_GPIO_FSEL_OUTP));
        bcm2835_gpio_fsel(pin => LCD_SI, mode => unsigned_char(BCM2835_GPIO_FSEL_OUTP));
    end io_init;


    procedure lcd_init is
    begin
        -- reset
        bcm2835_gpio_write(pin => LCD_CS, on => unsigned_char(HIGH));
        bcm2835_delayMicroseconds(unsigned_long_long(1));
        bcm2835_gpio_write(pin => LCD_RST, on => unsigned_char(LOW));
        bcm2835_delayMicroseconds(unsigned_long_long(1));
        bcm2835_gpio_write(pin => LCD_RST, on => unsigned_char(HIGH));
        bcm2835_delayMicroseconds(unsigned_long_long(1));
        -- init routine
        for index in lcd_init_data'range loop
            lcd_transfer_data(value => lcd_init_data(index), si => false);
        end loop;
        lcd_clear;
    end lcd_init;


    -- display strings on the lcd at a given position
    -- data is a string with any allowed range
    -- for strings not beginning at 0 we have to decrement the index
    -- variable for xpos by the value of the range begin, so we get
    -- for xpos a range from (xpos + 0 .. xpos + number of char in string)  
    procedure lcd_ascii57_string (xpos : natural; ypos : natural; data : string) is
    begin
        for index in data'range loop
            lcd_ascii57(xpos => xpos + (index - data'first) * 6, ypos => ypos, data => character'val(character'pos(data(index))));
        end loop;
    end lcd_ascii57_string;


    procedure lcd_ascii57 (xpos : natural; ypos : natural; data : character) is
    begin
        lcd_set_page(page => ypos, column => xpos);
        -- write one 5x7 char
        for index in 0..4 loop
            lcd_transfer_data(value => font_5x7(character'pos(data))(index), si => true);
        end loop;
        -- one free column between chars
        lcd_transfer_data(value => 16#00#, si => true);
    end lcd_ascii57;


    procedure lcd_picture (xpos : natural; ypos: natural) is
    begin
        for outdex in 0..7 loop 
            lcd_set_page(page => ypos + outdex, column => xpos);
            for index in (128 * outdex) .. (128 * (outdex + 1) - 1) loop
              lcd_transfer_data(value => picture(index), si => true);
            end loop;
        end loop;
    end lcd_picture;


    procedure lcd_clear is
    begin
        bcm2835_gpio_write(pin => LCD_CS, on => unsigned_char(LOW));
        for outdex in 0..7 loop
            lcd_set_page(page => outdex, column => 0);
            for index in 0..128 loop
                lcd_transfer_data(value => 16#00#, si => true);
            end loop;
        end loop;
        bcm2835_gpio_write(pin => LCD_CS, on => unsigned_char(HIGH));
    end lcd_clear;


    procedure lcd_transfer_data (value : byte; si : boolean) is
    begin
        bcm2835_gpio_write(pin => LCD_CS, on => unsigned_char(LOW));
        bcm2835_gpio_write(pin => LCD_CLK, on => unsigned_char(HIGH));
        if si then
            bcm2835_gpio_write(pin => LCD_A0, on => unsigned_char(HIGH));
        else
            bcm2835_gpio_write(pin => LCD_A0, on => unsigned_char(LOW));
        end if;
        lcd_byte(value);
        bcm2835_gpio_write(pin => LCD_CS, on => unsigned_char(HIGH));
    end lcd_transfer_data;


    procedure lcd_set_page (page : natural; column : natural) is
        lsb      : byte := byte(column + 1) and 16#0f#;
        msb      : byte := byte(column + 1) and 16#f0#;
        page_int : byte := byte(page)   or  16#b0#;
    begin
        msb := Shift_Right(msb, 4);
        msb := msb or 16#10#;
        lcd_transfer_data(value => page_int, si => false);
        lcd_transfer_data(value => msb, si => false);
        lcd_transfer_data(value => lsb, si => false);
        null;
    end lcd_set_page;


    procedure lcd_byte (data : byte) is
        data_int : byte := data;
    begin
        for index in 0..7 loop
            bcm2835_delayMicroseconds(unsigned_long_long(1));
            bcm2835_gpio_write(pin => LCD_CLK, on => unsigned_char(LOW));
            if (data_int and 16#80#) = 16#80# then
                bcm2835_gpio_write(pin => LCD_SI, on => unsigned_char(HIGH));
            else
                bcm2835_gpio_write(pin => LCD_SI, on => unsigned_char(LOW));
            end if;
            data_int := Shift_Left(data_int, 1);
            bcm2835_delayMicroseconds(unsigned_long_long(1));
            bcm2835_gpio_write(pin => LCD_CLK, on => unsigned_char(HIGH));
        end loop;
    end lcd_byte;


end RaspiLcd;