| View previous topic :: View next topic |
| Author |
Message |
Onur
Joined: 11 Apr 2004
Posts: 11
|
|
 Posted: Thu Aug 05, 2004 4:20 pm |
 |
|
This is code
| Code: |
#include <18F452.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=19200, xmit=PIN_E0, rcv=PIN_E1)
void main()
{
while(1)
{
getc();
puts("onur");
}
}
|
This is list
CCS PCH C Compiler, Version 3.203, 16465
Filename: C:\WINDOWS\Desktop\v\ooooo.LST
ROM used: 220 bytes (1%)
Largest free fragment is 32548
RAM used: 6 (0%) at main() level
7 (0%) worst case
Stack: 1 locations
*
0000: GOTO 00A4
.................... #include <18F452.h>
.................... //////// Standard Header file for the PIC18F452 device ////////////////
.................... #device PIC18F452
.................... #list
....................
....................
.................... #fuses HS,NOWDT,NOPROTECT,NOLVP
.................... #use delay(clock=20000000)
.................... #use rs232(baud=19200, xmit=PIN_E0, rcv=PIN_E1)
001A: MOVLW 08
001C: MOVWF 00
001E: BSF F96.1
0020: BTFSC F84.1
0022: BRA 0020
0024: CLRF 06
0026: BSF 00.7
0028: BRA 0046
002A: BCF 00.7
002C: BRA 0046
002E: BCF FD8.0
0030: BTFSC F84.1
0032: BSF FD8.0
0034: RRCF 06,F
0036: BSF 00.6
0038: BRA 0046
003A: BCF 00.6
003C: DECFSZ 00,F
003E: BRA 002E
0040: MOVFF 06,01
0044: BRA 005E
0046: MOVLW 50
0048: BTFSC 00.7
004A: MOVLW 15
004C: MOVWF 01
004E: DECFSZ 01,F
0050: BRA 004E
0052: NOP
0054: BTFSC 00.7
0056: BRA 002A
0058: BTFSC 00.6
005A: BRA 003A
005C: BRA 002E
005E: GOTO 00BA (RETURN)
0062: BCF F96.0
0064: BCF F8D.0
0066: MOVLW 08
0068: MOVWF 01
006A: NOP
006C: NOP
006E: NOP
0070: BSF 01.7
0072: BRA 0092
0074: BCF 01.7
0076: RRCF 07,F
0078: BTFSC FD8.0
007A: BSF F8D.0
007C: BTFSS FD8.0
007E: BCF F8D.0
0080: BSF 01.6
0082: BRA 0092
0084: BCF 01.6
0086: DECFSZ 01,F
0088: BRA 0076
008A: NOP
008C: NOP
008E: NOP
0090: BSF F8D.0
0092: MOVLW 50
0094: MOVWF FE9
0096: DECFSZ FE9,F
0098: BRA 0096
009A: BTFSC 01.7
009C: BRA 0074
009E: BTFSC 01.6
00A0: BRA 0084
00A2: RETLW 00
....................
.................... void main()
.................... {
00A4: CLRF FF8
00A6: BCF FD0.7
00A8: CLRF FEA
00AA: CLRF FE9
00AC: BSF FC1.0
00AE: BSF FC1.1
00B0: BSF FC1.2
00B2: BCF FC1.3
00B4: BCF F96.0
00B6: BSF F8D.0
.................... while(1)
.................... {
.................... getc();
00B8: BRA 001A
.................... puts("onur");
00BA: CLRF 06
00BC: MOVF 06,W
00BE: RCALL 0004
00C0: IORLW 00
00C2: BZ 00CC
00C4: INCF 06,F
00C6: MOVWF 07
00C8: RCALL 0062
00CA: BRA 00BC
00CC: MOVLW 0D
00CE: MOVWF 07
00D0: RCALL 0062
00D2: MOVLW 0A
00D4: MOVWF 07
00D6: RCALL 0062
.................... }
00D8: BRA 00B8
.................... }
....................
00DA: SLEEP
Configuration Fuses:
Word 1: 2200 HS NOOSCSEN
Word 2: 0E0F BROWNOUT WDT128 NOWDT BORV20 NOPUT
Word 3: 0100 CCP2C1
Word 4: 0081 STVREN NODEBUG NOLVP
Word 5: C00F NOPROTECT NOCPD NOCPB
Word 6: E00F NOWRT NOWRTD NOWRTB NOWRTC
Word 7: 400F NOEBTR NOEBTRB
|
|
 |
Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
|
|
| Posted: Thu Aug 05, 2004 7:04 pm |
|
|
| The source code compiles exactly as mine and works perfectly. Now I did test it at 10MHz because I didn't have a 20Mhz crystal at home. I think either your circuit it bad or your chip. Describe you circuit to us. |
|
|
Onurr
Guest
|
|
| Posted: Fri Aug 06, 2004 4:39 am |
|
|
| My circuit board is works fine. If I use 16f877 works fine... |
|
|
Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
|
|
| Posted: Fri Aug 06, 2004 4:46 am |
|
|
| The code works just fine on my circuit board and 18f452. Must be your chip or the circuit. For all I know, you circuit is crap and the 16F877 just barely works where there is a slight electrical difference in the 18F452 that is causing it not to work. If you want help, then you should answer the questions. If you don't, keep using the 16F877. |
|
|
Guest
|
|
| Posted: Fri Aug 06, 2004 9:07 am |
|
|
ok I will make other demo board. I and I will change my 18F452.
Thank you... |
|
|
ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
|
|
| Posted: Sat Aug 07, 2004 7:18 am |
|
|
Onur,
Mark didn't say you have to create a new demo board, he just asked you to describe the hardware you are using because this is the most likely reason left for failure. I asked you too for a description of your RS-232 interface and you never answered to that either.
You can create a new demo board, but without design changes it is very likely to fail again. What do you have against describing your schematics? Afraid of us copying your design? We have already seen so many RS-232 designs in this forum that I don't think you can come up with something completely new.
It's even possible that the problem is not in your design after all, reading this forum you can find many other causes for RS232 to fail. Although without checking your hardware it would be a waste of time to go into that deeper now. |
|
|
Guest
|
|
| Posted: Mon Aug 23, 2004 9:15 pm |
|
|
ckielstra
I'm sorry fistly I cant understand your questions. You are wrong thing about me. I want to learn something about pic.
I'm using simple rs232 interface. max232 and 4 cap. (10 uF)
and I connected to pic and com port. that is all
when I use this demo board 877 works but 452 cant work.
I'm saying not rs232 I'm talking about many program.
I tryed lots of program about 18f852 but lots of time program cant work. but sometime code work but some time cant work. I said myself maybe osilator must be change. then I used 4 mhz osi and code sometime works. If used 10 mhz osi some time works some times dont work..
and 10mhz osi and pllx4 newer worked.
If you want to know more things please ask me...... |
|
|
Ttelmah
Guest
|
|
| Posted: Tue Aug 24, 2004 3:05 am |
|
|
| Anonymous wrote: | ckielstra
I'm sorry fistly I cant understand your questions. You are wrong thing about me. I want to learn something about pic.
I'm using simple rs232 interface. max232 and 4 cap. (10 uF)
and I connected to pic and com port. that is all
when I use this demo board 877 works but 452 cant work.
I'm saying not rs232 I'm talking about many program.
I tryed lots of program about 18f852 but lots of time program cant work. but sometime code work but some time cant work. I said myself maybe osilator must be change. then I used 4 mhz osi and code sometime works. If used 10 mhz osi some time works some times dont work..
and 10mhz osi and pllx4 newer worked.
If you want to know more things please ask me...... |
Immediate suspicion is the crystal.
The oscillator circuit on the 18F chips, has higher gain that that on the 16F chips. The PLL will not work properly (will run off frequency), if even slightly overdriven. Hence it may be necessary to add a series resistor between the crystal, and the clock input pin (typically about 50ohms). The latter revisions of the chips are better in this regard, and normally the plain oscillator (without the PLL), is not so badly affected. I suspect you have a particularly high gain crystam, and it is perhaps locking onto a higher overtone. The code then won't work, since the UART timings will be completely wrong. Presumably you have the right loading capacitors on the crystal?.
Best Wishes |
|
|
Onurr
Guest
|
|
| Posted: Tue Aug 24, 2004 2:56 pm |
|
|
I used 22pf Condancator for 10 mhz osilator.
where can I find pll osilator? I dont know what is look like
where can I find schemtic about pll oscilator. |
|
|
ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
|
|
| Posted: Wed Aug 25, 2004 3:18 am |
|
|
Onur,
Thanks for describing your RS232 circuit. In this forum many different rs-232 circuits have been described and many things can go wrong here. Your setup is very standard and it isn't likely this is causing your problems.
This is the first time you mention other programs to fail, this changes the whole perspective and we will have to look for the error to be in another circuit than the RS232. Like Ttelmah said, the oscillator is the most likely cause of your problems.
2 x 22pf capacitors for a 10MHz crystal seem ok to me.
| Quote: | | where can I find pll osilator? I dont know what is look like |
The PLL oscillator is in the PIC. You yourself mentioned using it by selecting the pll4x option.
Have you tried adding a series resitors as Ttelmah suggested?
Another difference between PIC16 and PIC18 is that the PIC18 requires a parallel cut crystal, series cut crystals are not allowed as this may give an unspecified frequency.
If you want to make sure the oscillator is the problem you could write a small test program that toggles an output every 10 seconds. Use a voltmeter or LED to check the frequency of this output changing, if this is not every 10 seconds you know for sure it is the oscillator. |
|
|
onurr
Guest
|
|
| Posted: Wed Aug 25, 2004 4:00 pm |
|
|
| Quote: | | Have you tried adding a series resitors |
I must add 2 resistor or 1 resistor ?
osc1 pin or osc 2 pin?
| Quote: | | Another difference between PIC16 and PIC18 is that the PIC18 requires a parallel cut crystal, series cut crystals are not allowed as this may give an unspecified frequency. |
when I buy crystal I must be say parallel cut crystal
or those are same crystal
| Quote: | | If you want to make sure the oscillator is the problem you could write a small test program that toggles an output every 10 seconds. Use a voltmeter or LED to check the frequency of this output changing, if this is not every 10 seconds you know for sure it is the oscillator. |
yes I tested this:) this is changing maybe 10sec some time maybe 13 sec[/quote] |
|
|
ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
|
|
| Posted: Thu Aug 26, 2004 2:27 am |
|
|
I'm not an crystal expert, but looking at the PIC18 datasheets and searching the web I found the answers to all your questions. Maybe you could try and do the same?
| Quote: | I must add 2 resistor or 1 resistor ?
osc1 pin or osc 2 pin? |
It depends on the type of crystal you are using whether you need a resistor or not. Can you get more information from your supplier? Most crystals are AT-cut or AT-strip cut. For the AT-cut you don't need the resistor, for the AT-strip cut it may be required.
See PIC18F252 datasheet Figure 2-1: 1 resistor on osc2 pin. No value for the resistor is specified but something like 330 ohm should do it.
| Quote: | when I buy crystal I must be say parallel cut crystal
or those are same crystal |
You must specify series or parallel resonance when you buy the crystal. Both the same physical crystal, but they are specified for different frequencies. Using a series crystal in a parallel circuit (like the PIC uses) will result in a unspecified frequency and might even be out of manufacturer's specification. See this article for more information. |
|
|
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
