/*=========================================================
  STM8 + 16x2 LCD (4-bit mode) - COSMIC C
  Example target: STM8S103F3 / STM8S003
=========================================================*/

#include "iostm8s103f3.h"

/* LCD control pins on Port D */
#define LCD_RS_PORT   PD_ODR
#define LCD_RS_DDR    PD_DDR
#define LCD_RS_CR1    PD_CR1
#define LCD_RS_PIN    2

#define LCD_E_PORT    PD_ODR
#define LCD_E_DDR     PD_DDR
#define LCD_E_CR1     PD_CR1
#define LCD_E_PIN     3

/* LCD data pins D4-D7 on Port C */
#define LCD_D4_PORT   PC_ODR
#define LCD_D4_DDR    PC_DDR
#define LCD_D4_CR1    PC_CR1
#define LCD_D4_PIN    4

#define LCD_D5_PORT   PC_ODR
#define LCD_D5_DDR    PC_DDR
#define LCD_D5_CR1    PC_CR1
#define LCD_D5_PIN    5

#define LCD_D6_PORT   PC_ODR
#define LCD_D6_DDR    PC_DDR
#define LCD_D6_CR1    PC_CR1
#define LCD_D6_PIN    6

#define LCD_D7_PORT   PC_ODR
#define LCD_D7_DDR    PC_DDR
#define LCD_D7_CR1    PC_CR1
#define LCD_D7_PIN    7

/* Small delay using NOP */
static void delay_cycles(volatile unsigned long n)
{
    while (n--)
    {
        __asm("nop");
    }
}

/* Approximate millisecond delay
   Adjust loop count according to system clock */
static void delay_ms(unsigned int ms)
{
    unsigned int i;
    while (ms--)
    {
        for (i = 0; i < 1600; i++)
        {
            __asm("nop");
        }
    }
}

/* Configure LCD GPIO pins as push-pull outputs */
static void gpio_init(void)
{
    /* RS and E as output push-pull */
    LCD_RS_DDR |= (1 << LCD_RS_PIN);
    LCD_RS_CR1 |= (1 << LCD_RS_PIN);

    LCD_E_DDR  |= (1 << LCD_E_PIN);
    LCD_E_CR1  |= (1 << LCD_E_PIN);

    /* D4-D7 as output push-pull */
    LCD_D4_DDR |= (1 << LCD_D4_PIN);
    LCD_D4_CR1 |= (1 << LCD_D4_PIN);

    LCD_D5_DDR |= (1 << LCD_D5_PIN);
    LCD_D5_CR1 |= (1 << LCD_D5_PIN);

    LCD_D6_DDR |= (1 << LCD_D6_PIN);
    LCD_D6_CR1 |= (1 << LCD_D6_PIN);

    LCD_D7_DDR |= (1 << LCD_D7_PIN);
    LCD_D7_CR1 |= (1 << LCD_D7_PIN);
}

/* Write one logic value to a port pin */
static void lcd_set_pin(volatile unsigned char *port, unsigned char pin, unsigned char val)
{
    if (val)
        *port |=  (1 << pin);
    else
        *port &= ~(1 << pin);
}

/* Generate enable pulse */
static void lcd_pulse_enable(void)
{
    lcd_set_pin(&LCD_E_PORT, LCD_E_PIN, 0);
    delay_cycles(50);
    lcd_set_pin(&LCD_E_PORT, LCD_E_PIN, 1);
    delay_cycles(200);
    lcd_set_pin(&LCD_E_PORT, LCD_E_PIN, 0);
    delay_cycles(200);
}

/* Send 4-bit nibble to LCD */
static void lcd_write4(unsigned char nibble)
{
    lcd_set_pin(&LCD_D4_PORT, LCD_D4_PIN, (nibble >> 0) & 0x01);
    lcd_set_pin(&LCD_D5_PORT, LCD_D5_PIN, (nibble >> 1) & 0x01);
    lcd_set_pin(&LCD_D6_PORT, LCD_D6_PIN, (nibble >> 2) & 0x01);
    lcd_set_pin(&LCD_D7_PORT, LCD_D7_PIN, (nibble >> 3) & 0x01);

    lcd_pulse_enable();
}

/* Send full byte in 4-bit mode
   rs = 0 for command, 1 for data */
static void lcd_write_byte(unsigned char rs, unsigned char data)
{
    lcd_set_pin(&LCD_RS_PORT, LCD_RS_PIN, rs);

    /* Send high nibble first */
    lcd_write4((data >> 4) & 0x0F);
    /* Then low nibble */
    lcd_write4(data & 0x0F);

    delay_ms(2);
}

/* Send LCD command */
static void lcd_cmd(unsigned char cmd)
{
    lcd_write_byte(0, cmd);
}

/* Send LCD data character */
static void lcd_data(unsigned char data)
{
    lcd_write_byte(1, data);
}

/* Initialize LCD in 4-bit mode */
static void lcd_init(void)
{
    delay_ms(40);

    lcd_set_pin(&LCD_RS_PORT, LCD_RS_PIN, 0);

    /* Standard 4-bit initialization sequence */
    lcd_write4(0x03);
    delay_ms(5);

    lcd_write4(0x03);
    delay_ms(2);

    lcd_write4(0x03);
    delay_ms(2);

    lcd_write4(0x02);   /* Switch to 4-bit mode */
    delay_ms(2);

    lcd_cmd(0x28);      /* 4-bit, 2 lines, 5x8 font */
    lcd_cmd(0x0C);      /* Display ON, cursor OFF */
    lcd_cmd(0x06);      /* Entry mode set */
    lcd_cmd(0x01);      /* Clear display */
    delay_ms(2);
}

/* Set cursor position */
static void lcd_gotoxy(unsigned char row, unsigned char col)
{
    unsigned char addr;

    if (row == 0)
        addr = 0x80 + col;
    else
        addr = 0xC0 + col;

    lcd_cmd(addr);
}

/* Print null-terminated string */
static void lcd_puts(const char *s)
{
    while (*s)
    {
        lcd_data((unsigned char)*s);
        s++;
    }
}

void main(void)
{
    /* Optional: set clock divider to full speed if supported */
    CLK_CKDIVR = 0x00;

    gpio_init();
    lcd_init();

    lcd_gotoxy(0, 0);
    lcd_puts("STM8 COSMIC");

    lcd_gotoxy(1, 0);
    lcd_puts("LCD Test OK");

    while (1)
    {
        /* Main loop */
    }
}

/*=========================================================
  STM32 + 16x2 LCD (4-bit mode) - COSMIC C
  Example target: STM32F103C8
=========================================================*/

#include "stm32f10x.h"

/* LCD pin mapping on GPIOA */
#define LCD_RS_PIN    0
#define LCD_E_PIN     1
#define LCD_D4_PIN    4
#define LCD_D5_PIN    5
#define LCD_D6_PIN    6
#define LCD_D7_PIN    7

/* Small delay using NOP */
static void delay_cycles(volatile unsigned long n)
{
    while (n--)
    {
        __asm("nop");
    }
}

/* Approximate millisecond delay
   Adjust according to MCU clock */
static void delay_ms(unsigned int ms)
{
    while (ms--)
    {
        delay_cycles(8000);
    }
}

/* Initialize GPIOA pins for LCD */
static void gpio_init(void)
{
    /* Enable GPIOA peripheral clock */
    RCC->APB2ENR |= RCC_APB2ENR_IOPAEN;

    /* Configure PA0, PA1, PA4, PA5, PA6, PA7
       as output push-pull, 2 MHz */
    GPIOA->CRL &= ~(
          (0xF << (LCD_RS_PIN * 4))
        | (0xF << (LCD_E_PIN  * 4))
        | (0xF << (LCD_D4_PIN * 4))
        | (0xF << (LCD_D5_PIN * 4))
        | (0xF << (LCD_D6_PIN * 4))
        | (0xF << (LCD_D7_PIN * 4))
    );

    GPIOA->CRL |= (
          (0x2 << (LCD_RS_PIN * 4))
        | (0x2 << (LCD_E_PIN  * 4))
        | (0x2 << (LCD_D4_PIN * 4))
        | (0x2 << (LCD_D5_PIN * 4))
        | (0x2 << (LCD_D6_PIN * 4))
        | (0x2 << (LCD_D7_PIN * 4))
    );
}

/* Write one logic value to a GPIO pin */
static void lcd_pin_write(unsigned char pin, unsigned char val)
{
    if (val)
        GPIOA->BSRR = (1U << pin);
    else
        GPIOA->BRR  = (1U << pin);
}

/* Generate enable pulse */
static void lcd_pulse_enable(void)
{
    lcd_pin_write(LCD_E_PIN, 0);
    delay_cycles(50);
    lcd_pin_write(LCD_E_PIN, 1);
    delay_cycles(300);
    lcd_pin_write(LCD_E_PIN, 0);
    delay_cycles(300);
}

/* Send 4-bit nibble to LCD */
static void lcd_write4(unsigned char nibble)
{
    lcd_pin_write(LCD_D4_PIN, (nibble >> 0) & 0x01);
    lcd_pin_write(LCD_D5_PIN, (nibble >> 1) & 0x01);
    lcd_pin_write(LCD_D6_PIN, (nibble >> 2) & 0x01);
    lcd_pin_write(LCD_D7_PIN, (nibble >> 3) & 0x01);

    lcd_pulse_enable();
}

/* Send full byte in 4-bit mode
   rs = 0 for command, 1 for data */
static void lcd_write_byte(unsigned char rs, unsigned char data)
{
    lcd_pin_write(LCD_RS_PIN, rs);

    /* Send high nibble first */
    lcd_write4((data >> 4) & 0x0F);
    /* Then low nibble */
    lcd_write4(data & 0x0F);

    delay_ms(2);
}

/* Send LCD command */
static void lcd_cmd(unsigned char cmd)
{
    lcd_write_byte(0, cmd);
}

/* Send LCD data character */
static void lcd_data(unsigned char data)
{
    lcd_write_byte(1, data);
}

/* Initialize LCD in 4-bit mode */
static void lcd_init(void)
{
    delay_ms(40);

    lcd_pin_write(LCD_RS_PIN, 0);

    /* Standard 4-bit initialization sequence */
    lcd_write4(0x03);
    delay_ms(5);

    lcd_write4(0x03);
    delay_ms(2);

    lcd_write4(0x03);
    delay_ms(2);

    lcd_write4(0x02);
    delay_ms(2);

    lcd_cmd(0x28);   /* 4-bit, 2 lines, 5x8 font */
    lcd_cmd(0x0C);   /* Display ON, cursor OFF */
    lcd_cmd(0x06);   /* Entry mode set */
    lcd_cmd(0x01);   /* Clear display */
    delay_ms(2);
}

/* Set cursor position */
static void lcd_gotoxy(unsigned char row, unsigned char col)
{
    if (row == 0)
        lcd_cmd(0x80 + col);
    else
        lcd_cmd(0xC0 + col);
}

/* Print null-terminated string */
static void lcd_puts(const char *s)
{
    while (*s)
    {
        lcd_data((unsigned char)*s);
        s++;
    }
}

int main(void)
{
    gpio_init();
    lcd_init();

    lcd_gotoxy(0, 0);
    lcd_puts("STM32 COSMIC");

    lcd_gotoxy(1, 0);
    lcd_puts("LCD Test OK");

    while (1)
    {
        /* Main loop */
    }
}