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JerryR
Joined: 07 Feb 2008 Posts: 167
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Setting BOR Enabled |
Posted: Sat Dec 10, 2011 4:20 pm |
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I am having a problem enabling BOR at 4.5 volts on a PIC18F4525. Using CCS PCWH 4.121 with MPLab 8.70 IDE. IDE in Release mode and compiled code. Flags set as below:
Code: |
#include <18F4525.h>
#DEVICE ICD=TRUE
#DEVICE ADC=10 *=16 //set adc resolution
#fuses H4,NOWDT,NOPROTECT,NOLVP,PUT
#fuses BORV45
#use delay(clock=32000000)
#use rs232(baud=4800, xmit=PIN_C5, rcv=PIN_C4,ERRORS,stream=PC)
#use rs232(baud=57600, xmit=PIN_C6, rcv=PIN_C7,ERRORS,Enable= Pin_B0,stream=RS485)
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After successful compile, MPLAB Configure/Configuration bits reports:
RWRT PWRT disabled
BOREN Brown-out reset disabled in hardware and software
BORV Maximum setting
Actual operation of target reveals BOR is indeed not enabled.
Routinely have enabled BOR using CCS IDE.
Any suggestions? I'm sure it's something pretty stupid!
Thanks for the help |
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edmundopt
Joined: 08 Dec 2011 Posts: 15 Location: Portugal
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Posted: Sat Dec 10, 2011 7:11 pm |
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maybe use
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JerryR
Joined: 07 Feb 2008 Posts: 167
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Posted: Sun Dec 11, 2011 8:42 am |
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edmundopt: Thanks for your reply. BOREN is not a valid flag for the PIC18F4525, and indeed it does produce a compiler error.
Anyone else have a suggestion? Is there a document anywhere that explains the CCS fuses?
Thanks |
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drh
Joined: 12 Jul 2004 Posts: 192 Location: Hemet, California USA
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Posted: Sun Dec 11, 2011 8:52 am |
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These are the brown out fuses for that device.
NOBROWNOUT, BROWNOUT_SW, BROWNOUT_NOSL
BROWNOUT, BORV45, BORV27, BORV20 _________________ David |
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JerryR
Joined: 07 Feb 2008 Posts: 167
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Posted: Sun Dec 11, 2011 9:36 am |
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Thanks for the reply David
Yes, I see these combinations in 18F4525.h. However, no combination of these bits enable brown-our reset at 4.5 volts. This is confirmed by viewing the configuration bits in MPLAB after compiling in RELEASE mode. MPLAB reports:
BOREN Brown-out reset disabled in hardware and software
BORV Maximum setting
I have been having problems with an old project where EEPROM is being corrupted on either power-up or power down. Brown out reset should fix the problem and I can't enable it.
I would like to enable BOR at 4.5 volts with flags. Shouldn't the following combination provide this?
Code: |
#include <18F4525.h>
#DEVICE ICD=TRUE
#DEVICE ADC=10 *=16
#fuses H4,NOWDT,NOPROTECT,NOLVP,PUT
#fuses BROWNOUT
#FUSES BORV45
#use delay(clock=32000000)
#use rs232(baud=4800, xmit=PIN_C5, rcv=PIN_C4,ERRORS,stream=PC)
#use rs232(baud=57600, xmit=PIN_C6, rcv=PIN_C7,ERRORS,Enable= Pin_B0,stream=RS485)
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Thanks again for the group's help. |
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Ttelmah
Joined: 11 Mar 2010 Posts: 19552
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Posted: Sun Dec 11, 2011 10:02 am |
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You need to get rid of the ICD=TRUE in your code, as well as changing to release mode.
#FUSES BROWNOUT,BORV45
is the correct combination, and does work.
Get rid of *=16. This only applies to PIC16 chips.
Best Wishes |
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JerryR
Joined: 07 Feb 2008 Posts: 167
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Posted: Sun Dec 11, 2011 10:13 am |
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Ttelmah:
Thanks for your reply. I'll give that a try.
All the best |
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