UART.rar_C8051F020 Uart1_The C Word

//----------------------------------------------------------------------------- // F02x_UARTs_STDIO_Polled_2UARTs.c //----------------------------------------------------------------------------- // Copyright 2006 Silicon Laboratories, Inc. // http://www.silabs.com // // Program Description: // // This program demonstrates configuration of UART0 and UART1 and includes // an example of how to overload the STDIO library functions to enable // selection of either UART0 or UART1 in code, via the "UART" global variable. // This way both UARTs can use the same pins and present messages. // // Pinout // // P0.0 digital push-pull UART TX // P0.1 digital open-drain UART RX // P1.6 digital push-pull LED // // How To Test: // // 1) Download code to a 'F02x device that is connected to a UART transceiver // 2) Connect serial cable from the transceiver to a PC // 3) On the PC, open HyperTerminal (or any other terminal program) and connect // to the COM port at <BAUDRATE> and 8-N-1 // 4) HyperTerminal will print a message if everything is working properly // // Obs: The designer must check that the required baud rate is reached and // that the error is within range for the application. // // // FID: 02X000005 // Target: C8051F02x // Tool chain: KEIL C51 7.50 / KEIL EVAL C51 // Command Line: None // // Release 1.0 // -Initial Revision (CG) // -24 JUL 2006 // //----------------------------------------------------------------------------- // Includes //----------------------------------------------------------------------------- #include <c8051f020.h> // SFR declarations #include <stdio.h> //----------------------------------------------------------------------------- // 16-bit SFR Definitions for 'F02x //----------------------------------------------------------------------------- sfr16 RCAP2 = 0xca; // Timer2 capture/reload sfr16 TMR2 = 0xcc; // Timer2 //----------------------------------------------------------------------------- // Global Constants //----------------------------------------------------------------------------- #define BAUDRATE 1200 // Baud rate of UART in bps // SYSCLK = System clock frequency in Hz #define SYSCLK (22118400L) //----------------------------------------------------------------------------- // Function Prototypes //----------------------------------------------------------------------------- void OSCILLATOR_Init (void); void PORT_Init_UART0 (void); void PORT_Init_UART1 (void); void UART0_Init (void); void UART1_Init (void); //----------------------------------------------------------------------------- // Global Variables //----------------------------------------------------------------------------- unsigned char UART; // Global variable -- when '0', UART0 // is used for stdio; when '1', UART1 // is used for stdio //----------------------------------------------------------------------------- // main() Routine //----------------------------------------------------------------------------- void main (void) { WDTCN = 0xde; // Disable watchdog timer WDTCN = 0xad; OSCILLATOR_Init (); // Initialize oscillator PORT_Init_UART0 (); // Initialize crossbar and GPIO UART0_Init (); // Initialize UART0 UART1_Init (); // Initialize UART1 while (1) { // print something to UART0 PORT_Init_UART0 (); // Configure Crossbar to pinout // UART0 TX and RX to P0.0 and P0.1 UART = 0; printf ("UART 0\n\n"); // now print something to UART1 PORT_Init_UART1 (); // Configure Crossbar to pinout // UART1 TX and RX to P0.0 and P0.1 UART = 1; printf ("UART 1\n\n"); } } //----------------------------------------------------------------------------- // Initialization Subroutines //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- // OSCILLATOR_Init //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // This function initializes the system clock to use the external 22.1184MHz // crystal. // //----------------------------------------------------------------------------- void OSCILLATOR_Init (void) { int i; // Software timer OSCICN |= 0x80; // Enable the missing clock detector // Initialize external crystal oscillator to use 22.1184 MHz crystal OSCXCN = 0x67; // Enable external crystal osc. for (i=0; i < 256; i++); // Wait at least 1ms while (!(OSCXCN & 0x80)); // Wait for crystal osc to settle OSCICN |= 0x08; // Select external clock source OSCICN &= ~0x04; // Disable the internal osc. } //----------------------------------------------------------------------------- // PORT_Init_UART0 //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // This function configures the crossbar and GPIO ports. // // P0.0 digital push-pull UART TX // P0.1 digital open-drain UART RX //----------------------------------------------------------------------------- void PORT_Init_UART0 (void) { XBR0 = 0x04; // Enable UART0 XBR1 = 0x00; XBR2 = 0x40; // Enable crossbar and weak pull-up P0MDOUT |= 0x01; // Set TX pin to push-pull } //----------------------------------------------------------------------------- // PORT_Init_UART1 //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // This function configures the crossbar and GPIO ports. // // P0.0 digital push-pull UART TX // P0.1 digital open-drain UART RX //----------------------------------------------------------------------------- void PORT_Init_UART1 (void) { XBR0 = 0x00; XBR1 = 0x00; XBR2 = 0x44; // Enable crossbar and weak pull-up // Enable UART1 P0MDOUT |= 0x01; // Set TX pin to push-pull } //----------------------------------------------------------------------------- // UART0_Init Variable baud rate, Timer 2, 8-N-1 //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // Configure UART0 for operation at <baudrate> 8-N-1 using Timer2 as // baud rate source. // //----------------------------------------------------------------------------- void UART0_Init (void) { CKCON = 0x20; // Timer2 uses the system clock T2CON = 0x34; // Timer2 used for TX and RX, enabled RCAP2 = - ((long) (SYSCLK/BAUDRATE)/32); TMR2 = RCAP2; TR2= 1; // Start Timer2 SCON0 = 0x50; // 8-bit variable baud rate; // 9th bit ignored; RX enabled // clear all flags TI0 = 1; // Indicate TX0 ready } //----------------------------------------------------------------------------- // UART1_Init //--------------------------------------------