//-----------------------------------------------------------------------------
// F02x_UART1_Interrupt.c
//-----------------------------------------------------------------------------
// Copyright 2006 Silicon Laboratories, Inc.
//
//
// Program Description:
//
// This program demonstrates how to configure the C8051F020 to write to and read
// from the UART interface. The program reads a word using the UART1 interrupts
// and outputs that word to the screen, with all characters in upperca
/
/
// How To Test:
//
// 1) Download code to a 'F02x device that is connected to a UART transceiver
// 2) Verify jumpers J6 and J9 are populated on the 'F02x TB.
// 3) Connect rial cable from the transceiver to a PC
// 4) On the PC, open HyperTerminal (or any other terminal program) and connect
// to the COM port at <BAUDRATE> and 8-N-1
// 5) Download and execute code on an 'F02x target board.
//
//
/
/ Target: C8051F02x
// Tool chain: Keil C51 7.50 / Keil EVAL C51
// Command Line: None
//
// Relea 1.0
// -Initial Revision (SM)
// -6 JUN 2007
//
//
//-----------------------------------------------------------------------------
// 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 115200 // Baud rate of UART in bps
// SYSTEMCLOCK = System clock frequency in Hz
#define SYSTEMCLOCK (22118400L)
//-----------------------------------------------------------------------------
// Function Prototypes
//-----------------------------------------------------------------------------
void OSCILLATOR_Init (void);
void PORT_Init (void);
void UART1_Init (void);
//-----------------------------------------------------------------------------
// Global Variables
/
/-----------------------------------------------------------------------------
#define UART_BUFFERSIZE 64
unsigned char UART_Buffer[UART_BUFFERSIZE];
unsigned char UART_Buffer_Size = 0;
unsigned char UART_Input_First = 0;
unsigned char UART_Output_First = 0;
unsigned char TX_Ready =1;
static char Byte;
//-----------------------------------------------------------------------------
// main() Routine
//-----------------------------------------------------------------------------
void main (void)
{
WDTCN = 0xde; // Disable watc
hdog timer
WDTCN = 0xad;
OSCILLATOR_Init (); // Initialize oscillator
PORT_Init (); // Initialize crossbar and GPIO
UART1_Init (); // Initialize UART1
EA = 1;
while (1)
{
/
/ If the complete word has been entered via the hyperterminal followed by
// carriage return
if((TX_Ready == 1) && (UART_Buffer_Size != 0) && (Byte == 13))
{
TX_Ready = 0; // Set the flag to zero
SCON1 = (SCON1 | 0x02); // Set transmit flag to 1
}
}
}
//-----------------------------------------------------------------------------
// Initialization Subroutines
/
/-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// OSCILLATOR_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters : None
//
// This function initializes the system clock to u 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 u 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 ttle
OSCICN |= 0x08; // Select external clock source
OSCICN &= ~0x04; // Disable the internal osc.
}
//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// 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 (void)
{
XBR0 = 0x00;
XBR1 = 0x00;
XBR2 = 0x44; // Enable crossbar and weak pull-up
// Enable UART1
P0MDOUT |= 0x01; // Set TX pin to push-pull
}
//-----------------------------------------------------------------------------
/
/ UART1_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters : None
//
// Configure the UART1 using Timer1, for <baudrate> and 8-N-1.
// This routine configures the UART1 bad on the following equation:
//
// Baud = (2^SMOD1/32)*(SYSTEMCLOCK*12^(T1M-1))/(256-TH1)
//
/
/ This equatio
n can be found in the datasheet, Mode1 baud rate using timer1.
// The function lect the proper values of the SMOD1 and T1M bits to allow
// for the proper baud rate to be reached.
//-----------------------------------------------------------------------------
void UART1_Init (void)
{
SCON1 = 0x50; // SCON1: mode 1, 8-bit UART, enable RX
TMOD &= ~0xF0;
TMOD |= 0x20; // TMOD: timer 1, mode 2, 8-bit reload
if ( (((SYSTEMCLOCK/BAUDRATE)/256)/16) < 1 )
{
PCON |= 0x10; // SMOD1 (PCON.4) = 1 --> UART1 baudrate
// divide-by-two disabled
CKCON |= 0x10; // Timer1 us the SYSTEMCLOCK
TH1 = - ((SYSTEMCLOCK/BAUDRATE)/16);
}
el if ( (((SYSTEMCLOCK/BAUDRATE)/256)/32) < 1 )
{
PCON &= ~0x10; // SMOD1 (PCON.4) = 0 --> UART1 baudrate
// divide-by-two enabled
CKCON |= 0x10; // Timer1 us the SYSTEMCLOCK
TH1 = - ((SYSTEMCLOCK/BAUDRATE)/32);
}
el if ( ((((SYSTEMCLOCK/BAUDRATE)/256)/16)/12) < 1 )
{
PCON |= 0x10; // SMOD1 (PCON.4) = 1 --> UART1 baudrate
// divide-by-two disabled
CKCON &= ~0x10; // Timer1 us the SYSTEMCLOCK/12
TH1 = - (((SYSTEMCLOCK/BAUDRATE)/16)/12);
}
el if ( ((((SYSTEMCLOCK/BAUDRATE)/256)/32)/12) < 1 )
{
PCON &= ~0x10; // SMOD1 (PCON.4) = 0 --> UART1 baudrate
// divide-by-two enabled
CKCON &= ~0x10; // Timer1 us the SYSTEMCLOCK/12
TH1 = - (((SYSTEMCLOCK/BAUDRATE)/32)/12);
}
TL1 = TH1; // init Timer1
TR1 = 1; // START Timer1
TX_Ready = 1; // Flag showing that UART can transmit
EIE2 = 0x40; // Enable UART1 interrupts
EIP2 = 0x40; // Make UART high priority
}
/
/-----------------------------------------------------------------------------
// Interrupt Service Routines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// UART1_Interrupt
//-----------------------------------------------------------------------------
//
// This routine is invoked whenever a character is entered or displayed on the
// Hyperterminal.
//
//-----------------------------------------------------------------------------
void UART1_Interrupt (void) interrupt 20
{
if ((SCON1 & 0x01) == 0x01)
{
// Check if a new word is being entered
if( UART_Buffer_Size == 0) {
UART_Input_First = 0; }
SCON1 = (SCON1 & 0xFE); //RI1 = 0;
Byte = SBUF1;
// Read a character from Hyperterminal
if (UART_Buffer_Size < UART_BUFFERSIZE)
{
UART_Buffer[UART_Input_First] = Byte; // Store character
UART_Buffer_Size++; // Update array's size
UART_Input_First++; // Update counter
}
}
if ((SCON1 & 0x02) == 0x02) // Check if transmit flag is t
{
SCON1 = (SCON1 & 0xFD);
if (UART_Buffer_Size != 1) // If buffer not empty
{
/
/ Check if a new word is being output
if ( UART_Buffer_Size == UART_Input_First )
{
UART_Output_First = 0;
}
// Store a character in the variable byte
Byte = UART_Buffer[UART_Output_First];
if ((Byte >= 0x61) && (Byte <= 0x7A)) { // If lower ca letter
Byte -= 32; }
SBUF1 = Byte;
UART_Output_First++; // Update counter
UART_Buffer_Size--; // Decrea array size
}
el
{
UART_Buffer_Size = 0; // Set the array size to 0
TX_Ready = 1; // Indicate transmission complete
}
}
}
//-----------------------------------------------------------------------------
// End Of File
/
/-----------------------------------------------------------------------------
