dsPIC33FJ128GP802 internal oscillator settings

[viki2000]

I have tried a simple LED blink 1s on and 1s off with the settings from page 25 of “DS70216C - Section 39. Oscillator for dsPIC33F/PIC24H”:
http://ww1.microchip.com/downloads/en/D ... 70216C.pdf
It does not work properly. It blinks too fast.
That means improper settings for oscillator registers.
MCLR has 10K attached to it and Watchdog Timer disabled.
The VDD is 3.2Vdc. VCAP is 10uF ceramic multilayer. Decoupling is 100nF. I use the 28pin PDIP package.
FC7 is v 7.2.1. Below it is the simple code used.

Could you help with the proper internal oscillator settings?

dsPIC33FJ128GP802_LED.fcfx

LED blink

(8.64 KiB) Downloaded 210 times

[Benj]

Hello,

We have code like this to configure the internal oscillator when using USB on the 16-bit PICs.

Maybe you need something like this in a C icon at the start of the program.

Code: Select all

          MX_UINT16 pll_startup_counter = 600;
          CLKDIVbits.PLLEN = 1;
          while(pll_startup_counter--);

LED flashing too fast means the chip is running faster then you have specified in the project options.

[viki2000]

dsPIC33FJ128GP802 Datasheet page 147 shows CLKDIV:
http://ww1.microchip.com/downloads/en/D ... 70292G.pdf

There is no PLLEN bit.

[viki2000]

Here is the C code with the settings that makes the dsPIC33FJ128GP802 run at (close to) 80MHz with internal oscillator:

Code: Select all

CLKDIVbits.PLLPRE=0;        // PLLPRE (N2) 0=/2
PLLFBD=41;                  // pll multiplier (M) = +2
CLKDIVbits.PLLPOST=0;       // PLLPOST (N1) 0=/2
//OSCCON=0x11A0;
//OSCTUN = 0;
while(!OSCCONbits.LOCK);    // wait for PLL ready

Below is the LED blink test code.

dsPIC33FJ128GP802_LED_OK.fcfx

LED BLINK OK - INTERNAL OSCILLATOR

(8.75 KiB) Downloaded 211 times