www.pudn.com > DSP281x_examples.rar > Example_281xSci_Echoback.c
// TI File $Revision: /main/2 $
// Checkin $Date: April 25, 2007 10:55:00 $
//###########################################################################
//
// FILE: Example_281xSci_Echoback.c
//
// TITLE: DSP281x Device SCI Echoback.
//
// ASSUMPTIONS:
//
// This program requires the DSP281x header files.
// As supplied, this project is configured for "boot to H0 RAM" operation.
//
// Connect the SCI-A port to a PC via a transciever and cable.
// The PC application 'hypterterminal' can be used to view the data
// from the SCI and to send information to the SCI. Characters recieved
// by the SCI port are sent back to the host.
//
// As supplied, this project is configured for "boot to H0 RAM"
// operation.
//
//
// DESCRIPTION:
//
//
// This test recieves and echo-backs data through the SCI-A port.
//
// 1) Configure hyperterminal:
// Use the included hyperterminal configuration file SCI_96.ht.
// To load this configuration in hyperterminal: file->open
// and then select the SCI_96.ht file.
// 2) Check the COM port.
// The configuration file is currently setup for COM1.
// If this is not correct, disconnect Call->Disconnect
// Open the File-Properties dialog and select the correct COM port.
// 3) Connect hyperterminal Call->Call
// and then start the 281x SCI echoback program execution.
// 4) The program will print out a greeting and then ask you to
// enter a character which it will echo back to hyperterminal.
//
// As is, the program configures SCI-A for 9600 baud with
// SYSCLKOUT = 150MHz and LSPCLK = 37.5 MHz
//
//
// Watch Variables:
// LoopCount for the number of characters sent
// ErrorCount
//
//
//###########################################################################
// $TI Release:$
// $Release Date:$
//###########################################################################
#include "DSP281x_Device.h" // DSP281x Headerfile Include File
#include "DSP281x_Examples.h" // DSP281x Examples Include File
// Prototype statements for functions found within this file.
void scia_echoback_init(void);
void scia_fifo_init(void);
void scia_xmit(int a);
void scia_msg(char *msg);
// Global counts used in this example
Uint16 LoopCount;
Uint16 ErrorCount;
void main(void)
{
Uint16 ReceivedChar;
char *msg;
// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP281x_SysCtrl.c file.
InitSysCtrl();
// Step 2. Initalize GPIO:
// This example function is found in the DSP281x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio(); Skipped for this example
// For this example, only init the pins for the SCI-A port.
// This function is found in the DSP281x_Sci.c file.
EALLOW;
GpioMuxRegs.GPFMUX.all=0x0030; // Select GPIOs to be Scia pins
// Port F MUX - x000 0000 0011 0000
GpioMuxRegs.GPGMUX.all=0x0030; // Select GPIOs to be Scib pins
// Port G MUX - x000 0000 0011 0000
EDIS;
// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts
DINT;
// Initialize PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.
// This function is found in the DSP281x_PieCtrl.c file.
InitPieCtrl();
// Disable CPU interrupts and clear all CPU interrupt flags:
IER = 0x0000;
IFR = 0x0000;
// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the interrupt
// is not used in this example. This is useful for debug purposes.
// The shell ISR routines are found in DSP281x_DefaultIsr.c.
// This function is found in DSP281x_PieVect.c.
InitPieVectTable();
// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP281x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
// Step 5. User specific code:
LoopCount = 0;
ErrorCount = 0;
scia_fifo_init(); // Initialize the SCI FIFO
scia_echoback_init(); // Initalize SCI for echoback
msg = "\r\n\n\nHello World!\0";
scia_msg(msg);
msg = "\r\nYou will enter a character, and the DSP will echo it back! \n\0";
scia_msg(msg);
for(;;)
{
msg = "\r\nEnter a character: \0";
scia_msg(msg);
// Wait for inc character
while(SciaRegs.SCIFFRX.bit.RXFIFST!=1) { } // wait for XRDY =1 for empty state
// Get character
ReceivedChar = SciaRegs.SCIRXBUF.all;
// Echo character back
msg = " You sent: \0";
scia_msg(msg);
scia_xmit(ReceivedChar);
LoopCount++;
}
}
// Test 1,SCIA DLB, 8-bit word, baud rate 0x000F, default, 1 STOP bit, no parity
void scia_echoback_init()
{
// Note: Clocks were turned on to the SCIA peripheral
// in the InitSysCtrl() function
SciaRegs.SCICCR.all =0x0007; // 1 stop bit, No loopback
// No parity,8 char bits,
// async mode, idle-line protocol
SciaRegs.SCICTL1.all =0x0003; // enable TX, RX, internal SCICLK,
// Disable RX ERR, SLEEP, TXWAKE
SciaRegs.SCICTL2.all =0x0003;
SciaRegs.SCICTL2.bit.TXINTENA =1;
SciaRegs.SCICTL2.bit.RXBKINTENA =1;
SciaRegs.SCIHBAUD =0x0001; // 9600 baud @LSPCLK = 37.5MHz.
SciaRegs.SCILBAUD =0x00E7;
SciaRegs.SCICTL1.all =0x0023; // Relinquish SCI from Reset
}
// Transmit a character from the SCI
void scia_xmit(int a)
{
while (SciaRegs.SCIFFTX.bit.TXFFST != 0) {}
SciaRegs.SCITXBUF=a;
}
void scia_msg(char * msg)
{
int i;
i = 0;
while(msg[i] != '\0')
{
scia_xmit(msg[i]);
i++;
}
}
// Initalize the SCI FIFO
void scia_fifo_init()
{
SciaRegs.SCIFFTX.all=0xE040;
SciaRegs.SCIFFRX.all=0x204f;
SciaRegs.SCIFFCT.all=0x0;
}
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// No more.
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