Pic18f67k22 + pll + intosc + debug = problem

[elt42at]

Hello!

There is a problem with my microchip pic18 circuit.

I am using internal oscillator and enabled PLL (4x multiplier)

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Code C - [expand]
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#pragma config FOSC = INTIO2  // Oscillator: Internal RC oscillator 
#pragma config PLLCFG = ON      // PLL x4 Enable bit: Enabled

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In my initialization of board i set primary clock source and PLL than wait for a while.

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Code C - [expand]
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OSCCON = 0x70; 
OSCCON2 = 0x00; 
OSCTUNE = 0xDF; 
DelayMs(250);

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Now, the problem is debugging.

I am using PICKIT3. In debug mode, the circuit and code running. When i press HALT button, MPLAB sayas

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Code C - [expand]
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Running...
Halting...
Target halted
 
PK3Err0031: Failed to get PC

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To be agree! I closed PLL then, debugging is worked perfect!

Is there any problem with PLL and DEBUG together!

Thanks!!!

 

[zia]

hi ur frequency after PLL never exceed to 40 Mhz. be carefull

 

[elt42at]

40mhz is the limit for debug? or pickit3?

my circuit runs perfect at 64mhz ( 16mhz intosc and 4x PLL )

Some times, i need to see some SFR values. So, i want to use DEBUG mode.

I am pushing HALT button. First debugger says unable to get PC value. Than i press run button, microchip runs but serial port baudrate and led blink timings are changing. I measeured that the rate is 4x slow. Like PLL stops. In this time debugger can HALT and shows me PC.

My friend can debug his same circuit in 32mhz ( 8mhz internal and 4xPLL ) with mplabX.

Also, is there any different with mplab8 and mplabX in debug preferences!

 

[zia]

i tested a circuit by setting freq higher then 40 then its start giving me error

 

[elt42at]

Thanks "zia"!

ok, i cant debug at64mhz but why debugger makes PLL disable when i press "RUN" ???

(i add OSCTUNEbits.PLLEN=1; in while(1) than it is solved.)

 

[zia]

gd best of luck