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pieter
Joined: 16 Jan 2011
Posts: 27
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| [How to] Pic24EP256 output Crystal or FPLLO freq. on a pin |
 Posted: Thu Mar 13, 2014 11:51 pm |
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| Code: |
// Manual Setup for Reference Clock Output
#include <C:\Program Files\PICC\Devices\24EP256GP204.h>
#device ADC=12
#FUSES WDT //Watch Dog Timer
#FUSES NOIESO //Internal External Switch Over mode disabled
#FUSES PLLWAIT //Use when PLL ready
#FUSES HS
#FUSES PR_PLL //Pimary oscillator
#FUSES OSCIO //OSC2 is general purpose output
#FUSES WPRES128 //Watch Dog Timer PreScalar 1:128
#FUSES WPOSTS16 //Watch Dog Timer PostScalar 1:32768
#use delay(clock = 128000000, crystal=8000000, RESTART_WDT)
#PRAGMA ZERO_RAM
#use fast_io(A)
#use fast_io(B)
#use fast_io(C)
//
#word REFOCON=0x074E // reference clock setup register
#word RP56=0x068C // Pin C8 reprogrammable address
//
//**********************************************************************************
//
main()
{
SET_TRIS_A(0xfb7f); // 1111 1011 0111 1111 my settings
SET_TRIS_B(0x041f); // 0000 0100 0001 1111
SET_TRIS_C(0xfc03); // 1111 1100 0000 0011 pin C8 is output
Output_A(0x0000); //0b7f);
Output_B(0x0000); //041f);
Output_C(0x0143); //0143);
//
// With the fuses above:
// Crystal = 8 mHz
// Pll multiplies clock to 128 mHz
// Output the CRYSTAL frequency or the FPLLO clock on Pin C8:
//
// REFOCON=0x3700; // CRYSTAL frequency to output as ref frequency registers div128
// REFOCON=0xB700; // measure freq on pin C8 with scope and multiply with 128 to get the crystal freq.
// or
REFOCON=0x2C00; // FPLLO clock div4096
REFOCON=0xAC00; // measure freq on pin C8 with scope and multiply with 4096 to get the FPLLO freq.
RP56=0x31; // set reference clock output on pin C8
//
while (TRUE) // main routine
{
RESTART_WDT(); // reset watchdog
delay_ms(500);
}
} |
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Fonky
Joined: 19 Oct 2014
Posts: 1
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| Posted: Sun Oct 19, 2014 10:33 am |
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/ With the fuses above:
// Crystal = 8 mHz
// Pll multiplies clock to 128 mHz
// Output the CRYSTAL frequency or the FPLLO clock on Pin C8:
//
// REFOCON=0x3700; // CRYSTAL frequency to output as ref frequency registers div128
// REFOCON=0xB700; // measure freq on pin C8 with scope and multiply with 128 to get the crystal freq.
// or
REFOCON=0x2C00; // FPLLO clock div4096
REFOCON=0xAC00; // measure freq on pin C8 with scope and multiply with 4096 to get the FPLLO freq.
RP56=0x31; // set reference clock output on pin C8
//
while (TRUE) // main routine
{
RESTART_WDT(); // reset watchdog
delay_ms(500);
_________________
Kick |
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