Electronic – HSPLL mode freezes 18F46K20 micro controller

pllxc8

COMPILER: XC8 v 1.30
micro: PIC18F46K20

I use this in CONFIG1H register to get 64MHz Fosc (and use PLL):

#pragma config FOSC = INTIO7 // 1001 = Internal oscillator block, CLKOUT 
                             // function on RA6, port function on RA7
OSCON.IDLEN = 1;    // 16 MHz (HFINTOSC drives clock directly)
OSCON.IRCF = 111;
OSCON.SCS = 00; // Primary clock (determined by   CONFIG1H[FOSC<3:0>]).
OSCTUNE.PLLEN = 1;  // enable PLL for 8 and 16MHz Fosc

And then uC runs at 64MHz and I get 64/4=16MHz signal on pin RA6 (as expected)

But when I tried 'HSPLL' – as in data sheet : 

 #pragma config FOSC = HSPLL // 0110 = HS oscillator, PLL enabled (Clock Frequency = 4 x FOSC1)

then it completely STALLS uC : !!! It would not even start after build and power up.

Any ideas ?

Best Answer

Page 31 of the datasheet has a section called "2.4.3 LP, XT, HS MODES". It has a diagram which shows the necessary external circuitry. By using HSPLL you are then using the HS mode with the PLL.

Page 27 has the following diagram, which I think is more helpful generally:

enter image description here

Then you know to what the macros are referring.

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