Discussion in "Project Help" started by    eddieprice    Jan 12, 2018.
Fri Jan 12 2018, 04:32 PM
#1
I am using a 16F84A for the first time and am having trouble with the oscillator. I am using a 4 MHz xtal with 22pf capacitors as shown in the PIC16F84A datasheet. I have used MPLAB IDE V8.91 to write the program. The simulation works fine, but the circuit doesn't. I have a small didgital oscilloscope and I would assume that I should be able to observe a square wave across the xtal - but there is nothing. This is my configuration code:-
__CONFIG _CP_OFF & _WDT_OFF & _PWRTE_ON & _XT_OSC
Any suggestions would be much apprciated.
Fri Jan 12 2018, 06:49 PM
#2
Sometimes the Configuration word has to be programmed separately.
Check your programming software to make sure the
Configuration word is being set correctly.

Check the reset pin is high after a short delay.
Check all your connections again.. and carefully.

Write a simple flashing LED program, does it work using
the R/C oscillator ?

FYI.. the 16F84A is now very old, and expensive, due to rarity value.
It is messy to program in assembly and has too little memory
to do much in C.
Consider moving to a newer device.



[ Edited Sat Jan 13 2018, 02:56 AM ]

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ExperimenterUK
Sun Apr 14 2019, 10:52 PM
@hassan malik post your problem in the "General help Guidance and Discussion" forum
Sun Apr 14 2019, 05:06 PM
RAJESH MAPARi
please send me code to interface atmega32 with 24c1024 serial eeprom
Sun Apr 14 2019, 01:33 PM
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hello sir i installed proteus 7.8 professional on window 7 ultimate and window 10 but there would be same errors onn both windows. the error is bad license key.please any one help me
Sun Apr 14 2019, 01:32 PM
hassan malik
hello sir i installed proteus 7.8 professional on window 7 ultimate and window 10 but there would be same errors onn both windows. the error is bad license key.
ExperimenterUK
Sat Apr 06 2019, 05:59 PM
@deshrar. Please post your question in 8051 forum
Sat Apr 06 2019, 07:43 AM
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Wed Apr 03 2019, 04:38 PM
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Wed Apr 03 2019, 02:45 AM
@Prudhvi. Please post your request in 8051 forum
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Hi,

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