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deltatech
Joined: 22 Apr 2006
Posts: 87
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| PIC18F13K50 Serial Problem |
 Posted: Sun Jul 24, 2011 1:36 pm |
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Hi I am trying to receive serial text from PIC18F13K50.
I can see some Zeros in the HEX window of the Serial Monitor. But Nothing in the ASCII Window.
http://imageshack.us/photo/my-images/16/serialmonitorimage.jpg/
I tried HyperTerminal also there is nothing being received in Hyperterminal either.
I have connected a Oscilloscope probe to TX Pin of the Pic there is a waveform as can be seen in the jpg attachment
http://imageshack.us/photo/my-images/190/oscilloscopeimage.jpg/
Can anyone please tell me what could be the problem here.
Many Thanks
| Code: |
#include <18F13K50.h> //
#fuses NOWDT, BROWNOUT, PUT, NOLVP
#use delay(clock=10000000)
#use rs232(baud=9600,parity=N,xmit=PIN_B7,rcv=PIN_B5,bits=8)
// M A I N
void main(void) {
while (1){
printf("hello");
}
} |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19504
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| Posted: Sun Jul 24, 2011 3:39 pm |
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What is your oscillator?.
You have not selected an oscillator fuse, so the chip will be running some default - probably the internal oscillator. It looks as if the waveform is about 50+% fast, so possibly clocking at something like 16MHz, rather than the 10Mhz you have everything set to use....
Select an oscillator.
Best Wishes |
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deltatech
Joined: 22 Apr 2006
Posts: 87
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| Posted: Sun Jul 24, 2011 4:50 pm |
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| Hi it is a external 10 MHz crystal |
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temtronic
Joined: 01 Jul 2010
Posts: 9225
Location: Greensville,Ontario
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| Posted: Sun Jul 24, 2011 4:53 pm |
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Also be sure to add 'errrors' to the use rs232(...) options..
and you do have a MAX232 or equal in your circuit right ??!! |
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deltatech
Joined: 22 Apr 2006
Posts: 87
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| Posted: Sun Jul 24, 2011 4:56 pm |
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| I am using the CCS Software Development kit. This has a RS232 ic built in. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Sun Jul 24, 2011 6:42 pm |
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| Quote: | I am using the CCS Software Development kit
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I looked at the following CCS page and I don't see anything with that name:
http://www.ccsinfo.com/content.php?page=development-kits
Post a link to CCS kit that you actually have.
| Quote: | it is a external 10 MHz crystal.
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Then you need to add the HS fuse to your #fuses statement.
Also, post your compiler version. It's given at the top of the .LST file,
which will be in your project directory. It's a 4-digit number in this
format: x.xxx |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19504
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| Posted: Mon Jul 25, 2011 2:05 am |
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| deltatech wrote: | | Hi it is a external 10 MHz crystal |
Good. The point is though that your _code_, does not use this.
You need the fuse selected to say what oscillator to use. You have no oscillator fuse in your code. hence the crystal won't be used. The code is _not_ running at 10MHz, from the waveforms published. The default for fuse bits, is for them to be set to '1', if not programmed to another state. The pattern 1x, on the oscillator selection fuses, selects the _internal_ clock.
HS says 'use the external crystal'.
Best Wishes |
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deltatech
Joined: 22 Apr 2006
Posts: 87
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| Posted: Mon Jul 25, 2011 5:47 am |
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Thanks PCM programmer . The KIT is called
ACE Kit
Sku: S-137
Compiler version is 4.093 |
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deltatech
Joined: 22 Apr 2006
Posts: 87
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| Posted: Mon Jul 25, 2011 5:51 am |
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Ttelmah thanks for your advice. But I don't know how to set the code for external crystal.
When I used the Project Wizard there was no option for selecting external crystal only the frequency was set to 10MHz.
Would be kind enough to send me this line of code.
Many Thanks |
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deltatech
Joined: 22 Apr 2006
Posts: 87
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| Posted: Mon Jul 25, 2011 6:38 am |
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I have added the following line to the fuse code but still there is nothing being received on hyper terminal
| Code: |
#fuses XT,HS, NOWDT, BROWNOUT, PUT, NOLVP |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19504
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| Posted: Mon Jul 25, 2011 7:34 am |
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You must _not_ enable two oscillators.
Just one. The oscillator fuses are 'either or' selections not 'turn on more as needed'. You need the HS fuse, not the XT fuse. Setting both, gives potentially an impossible combination. XT in fact overrides HS, and should probably work, but you also need to disable the PLL, the default is for this to be enabled, so you will be running at 40MHz, not 10MHz.
It is in the Wizard. Third line down in the fuses box. A pulldown offering you what type of oscillator to use.
| Code: |
#include <18LF13K50.h>
#device adc=10
#FUSES NOWDT, CPUDIV1, USBDIV1, HS, NOPLLEN, NOPCLKEN, NOFCMEN, NOIESO, NOBROWNOUT, NOLVP, NOXINST
#use delay(clock=10000000)
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Best Wishes |
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deltatech
Joined: 22 Apr 2006
Posts: 87
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| Posted: Mon Jul 25, 2011 8:24 am |
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Ttelmah I added the Fuses you advised the compiler didn't like NOPCLKEN I removed this fuse and compiled.
And it is working perfectly. Now I am getting text in hyperterminal perfect.
Thanks you your help you are great |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19504
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| Posted: Mon Jul 25, 2011 8:42 am |
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That depends on compiler version. The NOPCLKEN, is not in 4.099, but is there from a couple of versions latter. It controls whether the primary clock is enabled, or under software control.
Best Wishes |
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