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statechamp
Joined: 13 Apr 2009
Posts: 1
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| help for usart on pic18f1320 |
 Posted: Mon Apr 13, 2009 7:57 am |
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I have been working on programming this MCU for a senoir design project, and im have problems with the usart in the PIC18F1320. My project has to do with reading the received data and doing if statments and such based on what is received by the MCU. What i am trying to do is have a xbee module connected to the TX and RX pins. the thing that i am having a problem with is that in my program i can get the MCU to retrieve and transmit data, but i cannot read what is in the RCREG(receive register). Is there anyone that can help me? I will be really greatful, thanks.
this is my code ran at 4mhz and created in MPLAB IDE:
| Code: | #include "p18f1320.h"
#include "usart.h"
#include "sw_uart.h"
#include "delays.h"
#include "stdlib.h"
#include "timers.h"
int DATABYTE;
char data;
void main(){
OSCCON=0xEF;
OSCTUNE=0b00000010;
for(;;)
{
if(RCSTAbits.FERR=1)
{
RCREG=0;
}
if(RCSTAbits.OERR=1)
{
RCSTAbits.CREN=0;
RCSTA=0b10010000;
}
T0CON=0b11001101;
TRISB = 0;
TXSTA=0b00100010;
//THREE THINGS THAT WAS SAID FOR CONFIG. USART
TRISB=0b00010010;
ADCON1=0b01100000;
RCSTA=0b10010000;
//SET UP FOR THE BAUD RATE
BAUDCTL=0b0101010;
SPBRG=25;
TXSTA=0b00100000;
TXSTAbits.SYNC=0;
//interrupts
PIE1bits.TXIE=1;
PIE1bits.RCIE=1;
INTCONbits.GIE=1;
INTCONbits.PEIE=1;
//SETTING UP AN 8 BIT ASYNC MODE (USART PINS MAY HAVE TO BE SET UP AS INPUTS)
RCSTA=0b10000000;
SPBRG=25;
TXSTA=0b00100000;
//OTHER STUFF
while(PIR1bits.TXIF=0)
{
;
}
PIE1bits.TXIE=0;
TXREG=DATABYTE;
while(PIR1bits.RCIF=0)
{
;
}
DATABYTE=RCREG;
}
}
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I have been working on this for like the last month and i do not know where to read the information that is being put in the MCU.
_________________
thegoldenone34 |
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Ttelmah
Guest
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| Posted: Mon Apr 13, 2009 8:24 am |
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You are writing code like an assembler programmer, but using a compiler. Either go assembler, or let the compiler do it's job....
Now, you don't show the definitions you have used for the registers, so it is impossible to know whether the code should work.
Then, you are writing fixed value into the OSCTUNE register. This is basically a 'no no'. It means your code will only give the correct timings on the one chip, this tuning value was from. Again, let the compiler (and the chip itself), do it's job, and read the tuning value from the configuration memory, and load it for you.
Other problems. You are manually controlling TRIS, but do not show fast_io being selected. Without this, the compiler will be controlling the TRIS, and probably doing a better job than you....
Let the compiler do it's job.
Something like:
| Code: |
#include <18F1320.h>
#device adc=8
#FUSES NOWDT, INTRC_IO, NOFCMEN, BROWNOUT, BORV27, PUT, NOCPD, STVREN, NODEBUG, NOLVP, NOWRT, NOWRTD, NOWRTC, IESO, NOEBTR, NOEBTRB, MCLR, NOPROTECT, NOCPB, NOWRTB
#use delay(clock=4000000)
#use rs232(baud=9600,parity=N,xmit=PIN_B1,rcv=PIN_B4,bits=8,errors)
//Change to suit your required baud rate.
int DATABYTE;
char data;
void main()
{
setup_oscillator(OSC_4MHZ|OSC_INTRC);
//Most of this is not needed
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_timer_0(RTCC_INTERNAL);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
while (TRUE) {
DATABYTE=getc();
//You will only arrive here, when a character is received.
//The error checking is automatically done for you by selecting
//'ERRORS'. The compiler automatically loads OSCTUNE from the
//stored value, etc. etc....
}
}
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Best Wishes |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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Guest
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| Posted: Mon Apr 13, 2009 4:49 pm |
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OSCCON=0xEF; //freq to 4mhz
baudUSART(BAUD_IDLE_CLK_HIGH & BAUD_8_BIT_RATE& BAUD_WAKEUP_OFF& BAUD_AUTO_OFF); // set baud rate to clock to read high,8bit baud rate,no wake up, no autobaud
PORTB=0x00; //dont really know why i put this here lol
OpenTimer0 (T0_8BIT & T0_SOURCE_INT & T0_PS_1_1 );// OPEN TIMERO
CloseTimer1 ();//CLOSE TIMER1
CloseTimer2 ();//CLOSE TIMER1
OpenUSART(USART_TX_INT_OFF & USART_RX_INT_ON & USART_ASYNCH_MODE & USART_EIGHT_BIT & USART_CONT_RX & USART_BRGH_HIGH,25);//OPEN USART CONTINUOUS RX AT 9600 BAUD
while(1){
DATABYTE=getcUSART(); //READ FROM RCREG AND STORE IN DATABYTE
I TRYED TO GO OFF OF WHAT HAD BEEN GIVEN ME BEFORE, AND TRY TO USE MORE LIBRARY THEN ASSEMBLY BUT I AM STILL HAVING SOME PROBLEMS |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Apr 13, 2009 4:58 pm |
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Do you understand what the C18 compiler is ? Your code is written
for that compiler. It won't work with the CCS compiler. This forum
is about the CCS compiler. You're on the wrong forum.
This is the correct forum for you:
http://www.microchip.com/forums/tt.aspx?forumid=3 |
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