UART.rar_C8051F UART

//----------------------------------------------------------------------------- // F500_UART0_Interrupt.c //----------------------------------------------------------------------------- // Copyright 2008 Silicon Laboratories, Inc. // http://www.silabs.com // // Program Description: // // This program demonstrates how to configure the C8051F500 to write to and // read from the UART interface. The program reads a word using the UART // interrupts and outputs that word to the screen, with all characters in // uppercase. // // How To Test: // // 1) Ensure that jumpers are placed on J17 of the C8051F500 target board // that connect the P0.4 pin to the TX signal, and P0.5 to the RX signal // 2) Connect USB cable from the development board to a PC // 3) Specify the target baudrate in the constant <BAUDRATE> // 4) On the PC, open HyperTerminal (or any other terminal program) and connect // to the USB port (virtual com port) at <BAUDRATE>, 8 data bits, no parity, // 1 stop bit and no flow control // 5) Download and execute code on an 'F500 target board // 6) Type up to 64 characters into the Terminal and press Enter. The MCU // will then print back the characters that were typed // // Target: C8051F500 (Side A of a C8051F500-TB) // Tool chain: Keil C51 8.0 / Keil EVAL C51 // Command Line: None // // Release 1.0 / 10 MAR 2008 (GP) // -Initial Revision // //----------------------------------------------------------------------------- // Includes //----------------------------------------------------------------------------- #include <compiler_defs.h> #include <C8051F500_defs.h> // SFR declarations #include <stdio.h> //----------------------------------------------------------------------------- // Global CONSTANTS //----------------------------------------------------------------------------- #define SYSCLK 24000000 // SYSCLK frequency in Hz #define BAUDRATE 115200 // Baud rate of UART in bps //----------------------------------------------------------------------------- // Function PROTOTYPES //----------------------------------------------------------------------------- void SYSCLK_Init (void); void UART0_Init (void); void PORT_Init (void); INTERRUPT_PROTO (UART0_ISR, INTERRUPT_UART0); //----------------------------------------------------------------------------- // Global Variables //----------------------------------------------------------------------------- #define UART_BUFFERSIZE 64 U8 UART_Buffer[UART_BUFFERSIZE]; U8 UART_Buffer_Size = 0; U8 UART_Input_First = 0; U8 UART_Output_First = 0; U8 TX_Ready = 1; static U8 Byte; //----------------------------------------------------------------------------- // MAIN Routine //----------------------------------------------------------------------------- void main (void) { SFRPAGE = ACTIVE_PAGE; // Change for PCA0MD PCA0MD &= ~0x40; // Disable watchdog timer PORT_Init (); // Initialize Port I/O SYSCLK_Init (); // Initialize Oscillator UART0_Init (); // Initialize UART EA = 1; // Enable global interrutpts while (1) { // If the complete word has been entered via the terminal followed by // carriage return if((TX_Ready == 1) && (UART_Buffer_Size != 0) && (Byte == 13)) { TX_Ready = 0; // Set the flag to zero TI0 = 1; // Set transmit flag to 1 } } } //----------------------------------------------------------------------------- // Initialization Subroutines //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- // PORT_Init //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // Configure the Crossbar and GPIO ports. // // P0.4 digital push-pull UART TX // P0.5 digital open-drain UART RX // //----------------------------------------------------------------------------- void PORT_Init (void) { U8 SFRPAGE_save = SFRPAGE; SFRPAGE = CONFIG_PAGE; P0MDOUT |= 0x10; // Enable UTX as push-pull output XBR0 = 0x01; // Enable UART on P0.4(TX) and P0.5(RX) XBR2 = 0x40; // Enable crossbar and weak pull-ups SFRPAGE = SFRPAGE_save; } //----------------------------------------------------------------------------- // SYSCLK_Init //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // This routine initializes the system clock to use the internal oscillator // at its maximum frequency. // Also enables the Missing Clock Detector. //----------------------------------------------------------------------------- void SYSCLK_Init (void) { U8 SFRPAGE_save = SFRPAGE; SFRPAGE = CONFIG_PAGE; OSCICN |= 0x87; // Configure internal oscillator for // its maximum frequency RSTSRC = 0x04; // Enable missing clock detector SFRPAGE = SFRPAGE_save; } //----------------------------------------------------------------------------- // UART0_Init //----------------------------------------------------------------------------- // // Return Value : None // Parameters : None // // Configure the UART0 using Timer1, for <BAUDRATE> and 8-N-1. //----------------------------------------------------------------------------- void UART0_Init (void) { U8 SFRPAGE_save = SFRPAGE; SFRPAGE = CONFIG_PAGE; SCON0 = 0x10; // SCON0: 8-bit variable bit rate // clear RI0 and TI0 bits // Baud Rate = [BRG Clock / (65536 - (SBRLH0:SBRLL0))] x 1/2 x 1/Prescaler #if ((SYSCLK / BAUDRATE / 2 / 0xFFFF) < 1) SBRL0 = -(SYSCLK / BAUDRATE / 2); SBCON0 |= 0x03; // Set prescaler to 1 #elif ((SYSCLK / BAUDRATE / 2 / 0xFFFF) < 4) SBRL0 = -(SYSCLK / BAUDRATE / 2/ 4); SBCON0 &= ~0x03; SBCON0 |= 0x01; // Set prescaler to 4 #elif ((SYSCLK / BAUDRATE / 2 / 0xFFFF) < 12) SBRL0 = -(SYSCLK / BAUDRATE / 2 / 12); SBCON0 &= ~0x03; // Set prescaler to 12 #else SBRL0 = -(SYSCLK / BAUDRATE / 2 / 48); SBCON0 &= ~0x03; SBCON0 |= 0x02; // Set prescaler to 48 #endif SBCON0 |= 0x40; // Enable baud rate generator ES0 = 1; // Enable UART0 interrupts TX_Ready = 1; // Flag showing that UART can transmit SFRPAGE = SFRPAGE_save; } //----------------------------------------------------------------------------- // Interrupt Service Routines //----------------------------------------------------------------------------- //----------------------------------------------------------------------------- // UART0_Interrupt //----------------------------------------------------------------------------- // // This routine is invoked whenever a character is entered or displayed on the // Hyperterminal. // //----------------------------------------------------------------------------- INTERRUPT(UART0_ISR, INTERRUPT_UART0) { if (RI0 == 1) { if( UART_Buffer_Size == 0) // If new word is entered { UART_Input_First = 0; } RI0 = 0; // Clear interrupt flag Byte = SBUF0; // Read a character from UART if (UART_Buffer_Size < UART_BUFFERSIZE) { UA