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acm45
Joined: 29 Dec 2008
Posts: 18
Location: Italy
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| 16F88 PWM-serial compatibility |
 Posted: Mon Dec 29, 2008 4:23 am |
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Hi!
I want to control the duty cycle of the pwm by pc with the serial port, I woud like to use the TX, RX pin of portB (pin B5, B2).
I write this code:
| Code: |
#include <16F88.h>
#device adc=8
#FUSES NOWDT //No Watch Dog Timer
#FUSES XT //Crystal osc <= 4mhz for PCM/PCH , 3mhz to 10 mhz for PCD
#FUSES NOPUT //No Power Up Timer
#FUSES MCLR //Master Clear pin enabled
#FUSES NOBROWNOUT //No brownout reset
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOCPD //No EE protection
#FUSES NOWRT //Program memory not write protected
#FUSES NODEBUG //No Debug mode for ICD
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOFCMEN //Fail-safe clock monitor disabled
#FUSES NOIESO //Internal External Switch Over mode disabled
#use delay(clock=4000000)
#use rs232(baud=9600,parity=N,xmit=PIN_B5,rcv=PIN_B2,bits=8)
#include <stdlib.h>
#build (reset=0x1,interrupt=0x4) \\ for bloader
#ORG 0x0F00,0x0FFF {}
char string[6];
unsigned int duty_cycle = 0;
void main()
{
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_spi(SPI_SS_DISABLED);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DIV_BY_4,249,1);
setup_ccp1(CCP_PWM);
set_pwm1_duty(125);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
//Setup_Oscillator parameter not selected from Intr Oscillotar Config tab
// TODO: USER CODE!!
printf("Ready...\n\r");
while(1)
{
while(!kbhit());
gets(string);
printf("Received: %s\n\r",string);
duty_cycle = atoi(string);
set_pwm1_duty(duty_cycle);
}
}
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The pwm output is on Pin B0, the frequency and the initial duty cycle is ok!
I receive the "ready" string but the pic don't receive the values I send.
If I modify the serial pins like:
#use rs232(baud=9600,parity=N,xmit=PIN_A3,rcv=PIN_A2,bits=8)
it functions!
Why I can't use the B3,B5 pins as serial port? |
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andyfraser
Joined: 04 May 2004
Posts: 47
Location: UK
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| Posted: Mon Dec 29, 2008 4:36 am |
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From your code, it looks like you are using a bootloader.
Could it be that the bootloader is messing with the configuration of the hardware serial port on RB2 and RB5 ?
Try your code without the bootloader and see if that makes a difference.
Andy |
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acm45
Joined: 29 Dec 2008
Posts: 18
Location: Italy
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| Posted: Mon Dec 29, 2008 5:10 am |
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| Thank for the answer Andy but, I've just tried without the bootloader and doesn't function! |
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Ttelmah
Guest
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| Posted: Mon Dec 29, 2008 5:35 am |
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Remember you will need to change the build instruction to run without the bootloader.
Prove your serial hardware is working. You know the output side is OK, so write a simple program to echo the characters back, and see if you are actually receiving.
I really would suspect the bootloader.
As general 'comments', beware of your string length. You allow six characters for the incoming data, but 'gets', adds a terminating '\0', and most terminal programs, send CR+LF, so it'd not take much typed, to overflow the buffer. I'd set the buffer a little larger (perhaps 10 characters), and use the GET_STRING function from input.c, with a length limit added as being a lot safer.
You really need to use 'atol', not 'atoi'.
Best Wishes |
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acm45
Joined: 29 Dec 2008
Posts: 18
Location: Italy
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| Posted: Mon Dec 29, 2008 6:55 am |
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Thank you for the hint Ttelmah, I tested the serial hardware without the bootloader with a simple echo program.
It functions corectly only if I use pins different from B5, B2!
If I use B5 and B2, I can only receive data from pic!
The bootloader I use is the bloader (sparkfun), and needs B5,B2 as TX/RX, his test program (serial echo) functions correctly!
What can be wrong? |
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FvM
Joined: 27 Aug 2008
Posts: 2337
Location: Germany
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| Posted: Mon Dec 29, 2008 7:26 am |
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Remove this line, it's configuring RB2 as SDO.
| Code: | | setup_spi(SPI_SS_DISABLED); |
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acm45
Joined: 29 Dec 2008
Posts: 18
Location: Italy
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| Posted: Mon Dec 29, 2008 8:48 am |
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FvM you find the problem!!!
I removed the line and now all is ok!!!
Also with the bootloader, all ok!
Thank you very much!!!
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