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Bart
Joined: 12 Jul 2005
Posts: 49
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| Blinking led on 18F4550 |
 Posted: Mon Oct 03, 2005 2:42 pm |
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Hello all,
As I changing for 16F877 to the 18F4550, I wanted to test my new pic with the blinking led test.
I changed also from ICProg to WinPic800
Programming seems to go OK, verifieing and erasing is working.
But : I don't receive the expected blink rate. Changing to another pin ( another led with another color) works.
When I meassure the freq. (with a multimeter) it is about 40 khz.
So my led is constantly on.
Tryed to play already with other xtal without any result (changed from 20 mhz to 5.0688 mhz. with same 40 khz output on pin)
Anyone an idee ?
My code :
| Code: | // VERSION : 0.1.0 : blinking blue led
#include <18F4550.h>
#fuses HS,NOWDT,NOPUT,NOLVP,BROWNOUT,NOCPD,NOWRT
#use delay(clock=20000000)
void main()
{
while (TRUE)
{
output_HIGH(PIN_A0);
delay_ms(10000);
output_LOW(PIN_A0);
delay_ms(10000);
}
} |
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I like Skype (www.skype.com), my username is BplotM |
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VanHauser
Joined: 03 Oct 2005
Posts: 88
Location: Ploiesti, Romania
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| Posted: Mon Oct 03, 2005 3:52 pm |
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| Try changing the BROWNOUT fuse into NOBROWNOUT or add BORV20 fuse. Check your power supply voltage for a correct brown-out configuration. |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Mon Oct 03, 2005 5:09 pm |
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Read the data sheet. The 18F family it is not a Plug&Play device.
Itīs a complex uC plenty of modules and functions that must be configured
properly before start running.
| Code: |
// VERSION : 0.1.0 : blinking blue led
#include <18F4550.h>
#FUSES NOWDT //No Watch Dog Timer
#FUSES WDT128 //Watch Dog Timer uses 1:128 Postscale
#FUSES HS //High speed Osc (> 4mhz)
#FUSES NOPROTECT //Code not protected from reading
#FUSES BROWNOUT_NOSL //Brownout enabled during operation,
disabled during SLEEP
#FUSES BROWNOUT //Reset when brownout detected
#FUSES BORV20 //Brownout reset at 2.0V
#FUSES PUT //Power Up Timer
#FUSES NOCPD //No EE protection
#FUSES STVREN //Stack full/underflow will cause reset
#FUSES NODEBUG //No Debug mode for ICD
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18)
used for I/O
#FUSES NOWRT //Program memory not write protected
#FUSES NOWRTD //Data EEPROM not write protected
#FUSES IESO //Internal External Switch Over mode enabled
#FUSES FCMEN //Fail-safe clock monitor enabled
#FUSES PBADEN //PORTB pins are configured as analog input channels on
RESET
#FUSES NOWRTC //configuration not registers write protected
#FUSES NOWRTB //Boot block not write protected
#FUSES NOEBTR //Memory not protected from table reads
#FUSES NOEBTRB //Boot block not protected from table reads
#FUSES NOCPB //No Boot Block code protection
#FUSES MCLR //Master Clear pin enabled
#FUSES LPT1OSC //Timer1 configured for low-power operation
#FUSES NOXINST //Extended set extension and Indexed Addressing
mode disabled (Legacy mode)
#FUSES PLL1 //No PLL PreScaler
#use delay(clock=20000000)
void main()
{
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(FALSE);
setup_wdt(WDT_OFF);
setup_timer_0(RTCC_INTERNAL);
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(VREF_LOW|-2);
setup_low_volt_detect(FALSE);
setup_oscillator(False);
while (TRUE)
{
output_toggle(PIN_A0);
delay_ms(1000);
}
}
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Humberto |
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Bart
Joined: 12 Jul 2005
Posts: 49
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| Thanks for the reply's |
| Posted: Wed Oct 05, 2005 2:49 pm |
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Thanks for the reply's.
Problem is found : it was due to my MAX232 ic.
I think it generated to much noise on the power line.
Adding a cap between pin 15 and 16 on the MAX232 of 10uF solved the problem.
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