STM8S903K3 Microcontroller: Features, Specifications, and STVD STM8 Tutorial

				
					#include "stm8s903k3.h"
#include "stdio.h"

#define _COSMIC_

/*
  Since different compilers (RAISONANCE, COSMIC, IAR) have slightly different parameter and return value conventions for putchar and getchar,
  we use macros to define them accordingly. These macros are automatically added by the compiler.
*/

#ifdef _RAISONANCE_
 #define PUTCHAR_PROTOTYPE int putchar (char c)
 #define GETCHAR_PROTOTYPE int getchar (void)
#elif defined (_COSMIC_)
 #define PUTCHAR_PROTOTYPE char putchar (char c)
 #define GETCHAR_PROTOTYPE char getchar (void)
#else /* _IAR_ */
 #define PUTCHAR_PROTOTYPE int putchar (int c)
 #define GETCHAR_PROTOTYPE int getchar (void)
#endif /* _RAISONANCE_ */

// Function to send a character to UART1
PUTCHAR_PROTOTYPE
{
    UART1_DR = c;              // Send a character 'c' to UART1 data register
    while (!(UART1_SR & 0x40)); // Wait for transmission to complete (TXE flag)
    return (c);
}

// Function to receive a character from UART1
GETCHAR_PROTOTYPE
{
    #ifdef _COSMIC_
      char c = 0;
    #else
      int c = 0;
    #endif
    // Wait for new data to be received (RXNE flag)
    while (!(UART1_SR & 0x20));  
    // Read received data
    c = UART1_DR;
    return (c);
}

// Clock initialization function
void CLK_Init(void)
{
    // Enable the internal high-speed oscillator (HSI)
    CLK_ICKR |= 0x01; 
    CLK_CKDIVR = 0x00; // No clock division (16MHz)
    while (!(CLK_ICKR & 0x02)); // Wait for HSI to be ready
    CLK_SWR = 0xE1; // Use HSI as the system clock source
}

// UART1 initialization function
void UART1_Init(void)
{
    UART1_CR3 = 0x00; // Disable LIN mode, one stop bit, no SCK
    UART1_CR2 = 0x00; // Disable TX interrupt, RX interrupt, and others
    UART1_CR3 = 0x00; // Disable interrupts, no break frames
    UART1_BRR2 = 0x02; // Set baud rate (9600)
    UART1_BRR1 = 0x68; // Set baud rate (9600)
    UART1_CR2 = 0x0C; // Enable TX and RX
}

// Simple delay function (not very accurate, could be improved with a timer)
void delay(unsigned int x)
{
    unsigned int i, j;
    for (i = x; i > 0; i--)
        for (j = 300; j > 0; j--);
}

void main()
{
    unsigned char c;
    CLK_Init();      // Initialize system clock
    UART1_Init();    // Initialize UART1

    while(1)
    {
        printf("\n\rPlease enter a key: ");
        while (!(UART1_SR & 0x20)); // Wait for data to be received (RXNE flag)
        c = UART1_DR;  // Read received character
        printf("\n\rYou entered: %c.", c);  // Send the received character back to the user
    }
}