📄 f02x_uarts_stdio_polled_2uarts.c
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//-----------------------------------------------------------------------------
// 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
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters : None
//
// Configure the UART1 using Timer1, for <baudrate> and 8-N-1.
// This routine configures the UART1 based on the following equation:
//
// Baud = (2^SMOD1/32)*(SYSCLK*12^(T1M-1))/(256-TH1)
//
// This equation can be found in the datasheet, Mode1 baud rate using timer1.
// The function select 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 ( (((SYSCLK/BAUDRATE)/256)/16) < 1 )
{
PCON |= 0x10; // SMOD1 (PCON.4) = 1 --> UART1 baudrate
// divide-by-two disabled
CKCON |= 0x10; // Timer1 uses the SYSCLK
TH1 = - ((SYSCLK/BAUDRATE)/16);
}
else if ( (((SYSCLK/BAUDRATE)/256)/32) < 1 )
{
PCON &= ~0x10; // SMOD1 (PCON.4) = 0 --> UART1 baudrate
// divide-by-two enabled
CKCON |= 0x10; // Timer1 uses the SYSCLK
TH1 = - ((SYSCLK/BAUDRATE)/32);
}
else if ( ((((SYSCLK/BAUDRATE)/256)/16)/12) < 1 )
{
PCON |= 0x10; // SMOD1 (PCON.4) = 1 --> UART1 baudrate
// divide-by-two disabled
CKCON &= ~0x10; // Timer1 uses the SYSCLK/12
TH1 = - (((SYSCLK/BAUDRATE)/16)/12);
}
else if ( ((((SYSCLK/BAUDRATE)/256)/32)/12) < 1 )
{
PCON &= ~0x10; // SMOD1 (PCON.4) = 0 --> UART1 baudrate
// divide-by-two enabled
CKCON &= ~0x10; // Timer1 uses the SYSCLK/12
TH1 = - (((SYSCLK/BAUDRATE)/32)/12);
}
TL1 = TH1; // Initialize Timer1
TR1 = 1; // Start Timer1
SCON1 |= 0x02; // Indicate TX1 ready (TI1=1)
}
//-----------------------------------------------------------------------------
// Support Subroutines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// putchar
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters : None
//
// Configure the UART1 using Timer1, for <baudrate> and 8-N-1.
// This routine overloads the standard putchar() library function to support
// either UART0 or UART1, depending on the state of the global variable
// <UART>.
//
//-----------------------------------------------------------------------------
char putchar (char c)
{
if (UART == 0)
{
if (c == '\n') // If carriage return
{
while (!TI0);
TI0 = 0;
SBUF0 = 0x0d; // Output CR
}
while (!TI0); // Wait for transmit complete
TI0 = 0;
SBUF0 = c; // Send character
}
else if (UART == 1)
{
if (c == '\n') // If carriage return
{
while ((SCON1 & 0x02) == 0); // Wait for the transmit to complete
SCON1 &= ~0x02; // Clear TI1
SBUF1 = 0x0d; // Output CR
}
while ((SCON1 & 0x02) == 0); // Wait for the transmit to complete
SCON1 &= ~0x02; // Clear TI1
SBUF1 = c; // Send character
}
return c;
}
//-----------------------------------------------------------------------------
// _getkey
//-----------------------------------------------------------------------------
//
// Return Value : Char received throught serial port (UART0 or UART1)
// Parameters : None
//
// This routine overloads the standard _getkey() library function to support
// either UART0 or UART1, depending on the state of the global variable
// <UART>.
//-----------------------------------------------------------------------------
char _getkey ()
{
char c;
if (UART == 0)
{
while (!RI0); // Wait for byte to be received
c = SBUF0; // Read the byte
}
else if (UART == 1)
{
while ((SCON1 & 0x01) == 0); // Wait for the reception to complete
c = SBUF1; // Read the byte
}
return (c);
}
//-----------------------------------------------------------------------------
// End Of File
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