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PIC18LF4525 and RS232 issue

 
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FMOpt2000



Joined: 10 Jan 2008
Posts: 17

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PIC18LF4525 and RS232 issue
PostPosted: Thu Nov 10, 2011 3:18 am     Reply with quote
Hi, I'm using the PIC18LF4525.
I wrote a lot of firmware and it hasn't problem, but now, I have a problem with the serial port.
I've reduced the firmware at those few line.

Could you help me?
The signal on pin C6 is low and I don't see any activity.

Code:

#include <18F4525.h>
#device ICD=TRUE
#device adc=10
#FUSES NOWDT
#FUSES INTRC_IO                 //Internal RC Osc, no CLKOUT
#FUSES NOPROTECT                //Code not protected from reading
#FUSES IESO                     //Internal External Switch Over mode enabled
#FUSES NOBROWNOUT               //No brownout reset
#FUSES NOPUT                    //No Power Up Timer
#FUSES NOCPD                    //No EE protection
#FUSES STVREN                   //Stack full/underflow will cause reset
#FUSES NODEBUG                  //No Debug mode for ICD
#FUSES LVP                      //Low Voltage Programming on B3(PIC16) or B5(PIC18)
#FUSES NOWRT                    //Program memory not write protected
#FUSES NOWRTD                   //Data EEPROM not write protected
#FUSES NOEBTR                   //Memory not protected from table reads
#FUSES NOCPB                    //No Boot Block code protection
#FUSES NOEBTRB                  //Boot block not protected from table reads
#FUSES NOWRTC                   //configuration not registers write protected
#FUSES NOWRTB                   //Boot block not write protected
#FUSES FCMEN                    //Fail-safe clock monitor enabled
#FUSES NOXINST                  //Extended set extension and Indexed Addressing mode disabled (Legacy mode)



#use delay(clock=8000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)




Code:

#include "main.h"

char command;
int1 app_debug=0;
 
void main()
{
   setup_adc_ports(AN0_TO_AN2|VSS_VDD);
   setup_adc(ADC_CLOCK_INTERNAL|ADC_TAD_MUL_6);
   setup_psp(PSP_DISABLED);
   setup_spi(SPI_SS_DISABLED);
   //setup_timer_0(RTCC_INTERNAL);
   setup_wdt(WDT_OFF);
   setup_timer_0(RTCC_INTERNAL|RTCC_DIV_32);
   setup_timer_1(T1_DISABLED);
   setup_timer_2(T2_DISABLED,0,1);
   setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
   setup_comparator(NC_NC_NC_NC);
   setup_vref(FALSE);
   enable_interrupts(INT_TIMER0);
   enable_interrupts(GLOBAL);
   
   disable_interrupts(INT_RTCC);
   
   setup_oscillator(OSC_8MHZ|OSC_TIMER1|OSC_31250|OSC_PLL_OFF);

 
while(1)
   {
   command='U';
   putc(command);
 
  if(app_debug==1)
  {
  output_low(pin_d7);
  app_debug=0;
  delay_ms(255);
  }
  else
  {
  output_high(pin_d7);
  app_debug=1;
  delay_ms(255);
 
  }
}

}

Ttelmah



Joined: 11 Mar 2010
Posts: 19477

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PostPosted: Thu Nov 10, 2011 3:59 am     Reply with quote
Are you _sure_ you are using LVP?.
99.9% of programmers do not.
If you are, and with the LVP fuse selected as you have, you _must_ have a pull down resistor on the PGM pin (B5), or the chip won't run.

Secondary comment:

setup_spi(SPI_SS_DISABLED);

is the wrong syntax. The command to turn off SPI is:

setup_spi(FALSE);

This is a bug in the wizard (has been around for years.....).

Third comment. You momentarily enable INT_TIMER0, but don't show any handler for this. This risks crashing the chip. _Never_ enable an interrupt without a handler...

Fourth comment. Add the keyword 'ERRORS' to the #USE RS232 setup. This _must_ always be present, if using the hardware UART, unless _you_ add code to handle serial errors. If it is missed, and the RX input is not permanently high, the UART _will_ become hung.

Fifth comment. Look again at your setup_oscillator line. You can't have three oscillators all selected as the master oscillator.....
All you need is:

setup_oscillator(OSC_8MHZ);

Best Wishes
FMOpt2000



Joined: 10 Jan 2008
Posts: 17

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PostPosted: Thu Nov 10, 2011 9:02 am     Reply with quote
Thx!
I'm not sure about nothing!!
I'm a beginner and I did my schematic copying my colleagues.
I've an ICD-U40;I haven't the resistor on B5 and the PIC is running.

I'm going to correct like you say.

This is the problem on RS232:
I worked on a folder for a week, modifying the firmware.
After I have done a copy of my firmware folder and I've worked on this new folder (I've added the fuse for RS-232 to the main).

But the modify is applied on the old main file (not for the new folder)...

I thought the references were local references, not absolute references.
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