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SAMIR_SBG
Joined: 01 Nov 2007
Posts: 9
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| PIC18F14K50 UART Problem |
 Posted: Fri Jun 12, 2009 7:33 am |
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Hi,
I have made a small Eval board for PIC18F14K50 :
I have a PicKit 2 Programmer.
I use CCS Compiler v4.088.
I Uuse Proteus ISIS v7.4 SP3 for Simulation.
My problem is when I use Port_B5 to receiving a RS232 data it don't work on ISIS and on my Eval Board, but when I use another port like Port_B6 it work fine on ISIS and on my Eval board!!
Can someone help me if I have an error in my source code?
CCS source Code to transmit a receiver character:
| Code: | #include <18F14K50.h>
#fuses NOWDT,NOPROTECT,NOLVP
#fuses HS
#FUSES CPUDIV1
#use delay(clock=20M)
#use rs232(baud=57600,parity=N,xmit=PIN_B7,rcv=PIN_B6,bits=
#use fast_io (B)
void main()
{
char a;
while(1)
{
a=getc();
putc(a);
}
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Jun 12, 2009 11:39 am |
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The problem is that your version of the compiler does not have the
correct start-up code. It does not set all pins to be for digital i/o.
Also, the setup_adc_ports() function doesn't do this in your version.
So you have to fix it by writing directly to the ANSEL and ANSELH
registers. Add the lines shown in bold below:
| Quote: |
#include <18F14K50.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=57600,xmit=PIN_B7,rcv=PIN_B6)
#byte ANSEL = 0xF7E
#byte ANSELH = 0xF7F
//====================================
void main()
{
char a;
ANSEL = 0;
ANSELH = 0;
while(1)
{
a = getc();
putc(a);
}
}
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Also, you are selecting "fast i/o" mode on Port B, but you are not
setting the TRISB register. You're supposed to do that.
My advice is, don't use fast i/o. Leave it in "standard i/o" mode, which
is the default mode of the compiler. Then the compiler will set the TRIS
for you, automatically. You don't need to worry about it. |
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