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bionicbot
Joined: 05 Aug 2010
Posts: 5
Location: UK
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| Problem PLL and RS232 on dsPIC33FJ256MC710 |
 Posted: Thu Aug 05, 2010 8:09 am |
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Dear all,
I am a new user on dsPIC33Fxxxx. I use dsPIC33Fj256MC710 with RS232 and my code is shown below. This code can normally operate with 8MHz crystal.
| Code: |
#include <33FJ256MC710.h>
#fuses XT,PR,NOWDT,NOCOE,NODEBUG, NOWRTB, NOPUT, NOWRTSS, NOWRT, NOPROTECT, NORSS
#use delay(clock=8M)
#use rs232(baud=9600,uart1)
void main(void)
{
while(TRUE)
{
printf("Test dsPIC33F RS232 \n");
delay_ms(3000);
}
}
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But now I need to use PR_PLL to increase speed of cpu to 40 MIPs.
I have set the parameters as shown below. I cannot send data to RS232.
| Code: |
#include <33FJ256MC710.h>
#fuses XT,PR_PLL,NOWDT,NOCOE,NODEBUG, NOWRTB, NOPUT, NOWRTSS, NOWRT, NOPROTECT, NORSS
#use delay(clock=40M)
#use rs232(baud=9600,uart1)
void main(void)
{
while(TRUE)
{
printf("Test dsPIC33F RS232 \n");
delay_ms(3000);
}
}
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I have aready read this topic and tried but it doesn't work.
https://www.ccsinfo.com/forum/viewtopic.php?t=38529&highlight=dspic33fj256gp710
This is my code.
| Code: |
#include <33FJ256MC710.h>
#fuses XT,PR_PLL,NOWDT,NOCOE,NODEBUG, NOWRTB, NOPUT, NOWRTSS, NOWRT, NOPROTECT, NORSS
#use delay(clock=40M)
#use rs232(baud=9600,uart1) // rcv=PIN_F2, xmit=PIN_F3)
#word OSCCON = 0X0742 //OSCILLATOR CONTROL REGISTER
#word CLKDIV = 0X0744 //CLOCK DIVISOR REGISTER
#word PLLFBD = 0X0746//PLL FEEDBACK DIVISOR REGISTER
#bit CLKDIV0=CLKDIV.0//‘N1’, PLL prescaler ->N1=2
#bit CLKDIV1=CLKDIV.1
#bit CLKDIV2=CLKDIV.2
#bit CLKDIV3=CLKDIV.3
#bit CLKDIV6=CLKDIV.6//‘N2’, PLL prescaler ->N2=2
#bit CLKDIV7=CLKDIV.7
#bit CLKDIV11=CLKDIV.11//DOZE Mode Enable bit
#bit CLKDIV12=CLKDIV.12//Processor Clock Reduction Select bits->1:1
#bit CLKDIV13=CLKDIV.13
#bit CLKDIV14=CLKDIV.14
#bit OSCCON8=OSCCON.8
#bit OSCCON9=OSCCON.9
#bit OSCCON10=OSCCON.10
void main(void)
{
/*************************************************************
Second Modify this registers to custom value in main():
*************************************************************/
CLKDIV0=0;//‘N1’, PLL prescaler ->N1=2
CLKDIV1=0;
CLKDIV2=0;
CLKDIV3=0;
CLKDIV6=0;//‘N2’, PLL prescaler ->N2=2
CLKDIV7=0;
CLKDIV11=1;//DOZE Mode Enable bit
CLKDIV12=0;//Processor Clock Reduction Select bits->1:1
CLKDIV13=0;
CLKDIV14=0;
OSCCON8=1;//Primary oscillator (XT, HS, EC) with PLL
OSCCON9=1;
OSCCON10=0;
//PLLFBD=0b000011110;//‘M’, PLL multiplier->M=32
PLLFBD=0b000101000;//‘M’, PLL multiplier->M=40
while(TRUE)
{
printf("Test dsPIC33F RS232 \n");
delay_ms(3000);
}
} |
I'm not sure, am I doing something wrong? Anyone please advise me.
Thank you in advance. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19539
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| Posted: Thu Aug 05, 2010 10:04 am |
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You need to unlock the clock register, to set the configuration bits yourself. If I remember correctly, Fvm, has posted details of how to do this in the past. A search may find it.
The settings you are making will be ignored otherwise.
What version compiler are you on?.
The command:
#use delay(crystal=8000000,clock=40000000)
Should work now, but didn't till recently. What version compiler are you using?.
Best Wishes |
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bionicbot
Joined: 05 Aug 2010
Posts: 5
Location: UK
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| Posted: Thu Aug 05, 2010 10:28 am |
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Thank you very much Ttelmah. I used #use delay(crystal=8000000,clock=40000000) as you recommended. RS232 works good but I will check the real speed by using oscilloscope again
Thank you again. |
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