HD44780 LCD + XBee

lcd.c

#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>

#include "xbee.h"
#include "lcd.h"

static int send_sync(int fd, uint8_t *remote, char *cmd, uint8_t *data, uint16_t n)
{
        uint8_t rd[256];

        send_remote_at_command_request(fd, remote, cmd, data, n);
        return recv_response(fd, rd, &n);
}

static uint8_t on_off(int b)
{
        return b == 0? 0x04: 0x05;
}

static int rs(int fd, uint8_t *remote, int b)
{
        static int c = -1;

        if (b != c) {
                uint8_t x = on_off(b);
                c = b;
                return send_sync(fd, remote, "P1", &x, 1);
        }
        return 0;
}

static int enable(int fd, uint8_t *remote, int b)
{
        uint8_t x = on_off(b);
        return send_sync(fd, remote, "P2", &x, 1);
}

static int bit(int fd, uint8_t *remote, int i, int b)
{
        static char *lines[] = { "D0", "D1", "D2", "D3" };
        static int c[] = { -1, -1, -1, -1 };

        if (c[i] != b) {
                uint8_t x = on_off(b);
                c[i] = b;
                return send_sync(fd, remote, lines[i], &x, 1);

        }
        return 0;
}

static int nibble(int fd, uint8_t *remote, uint8_t n)
{
        int e = bit(fd, remote, 0, n & 1) ||
                bit(fd, remote, 1, n & 2) ||
                bit(fd, remote, 2, n & 4) ||
                bit(fd, remote, 3, n & 8) ||
                enable(fd, remote, 1) ||
                enable(fd, remote, 0) ||
                usleep(1000);
        return -e;
}

static int byte(int fd, uint8_t *remote, uint8_t n)
{
        int e = nibble(fd, remote, n >> 4) ||
                nibble(fd, remote, n & 0x0f);
        return -e;
}

int cmd_byte(int fd, uint8_t *remote, uint8_t n)
{
        int e = rs(fd, remote, 0) ||
                byte(fd, remote, n);
        return -e;
}

int print_char(int fd, uint8_t *remote, uint8_t n)
{
        int e = rs(fd, remote, 1) ||
                byte(fd, remote, n);
        return -e;
}

int print_str(int fd, uint8_t *remote, char *s)
{
        char c;
        while ((c = *s++))
                if (0 > print_char(fd, remote, c))
                        return -1;
        return 0;
}

int lcd_init(int fd, uint8_t *remote)
{
        // initialization in 4-bit mode
        int e = enable(fd, remote, 0) ||
                rs(fd, remote, 0) ||
                nibble(fd, remote, 0x03) ||
                usleep(5000) ||
                nibble(fd, remote, 0x03) ||
                usleep(5000) ||
                nibble(fd, remote, 0x03) ||
                usleep(1000) ||
                nibble(fd, remote, 0x02) ||
                cmd_byte(fd, remote, 0x28) ||
                cmd_byte(fd, remote, 0x0c) ||
                cmd_byte(fd, remote, 0x01) ||
                usleep(2000) ||
                cmd_byte(fd, remote, 0x06);
        return -e;
}