TMS320F28335: PLL cannot lock

Linda Zhang84708

Part Number: TMS320F28335

Hello Champs,

Would you please kindly suggest what will cause that F28335 PLL cannot lock during power-on?

Is there any possibility that PLLLOCKS is always 0 so that the codes will always wait in this "while" loop?

while(SysCtrlRegs.PLLSTS.bit.PLLLOCKS != 1)

{

// Uncomment to service the watchdog

//ServiceDog();

}

Thanks!

Best Regards,

Linda

0 Todd Anderson78572 over 6 years ago

Guru 14640 points

Have you looked at the "Hardware Design Guidelines for TMS320F28xx and TMS320F28xxx DSCs" application note (SPRAAS1D)?

There are specific guidelines for external oscillators, and resulting PLL.

Hopefully, that helps.

0 Hareesh Janakiraman over 6 years ago in reply to Todd Anderson78572

What input clock source is used? Have you verified if the clock is actually present at the DSP pins?

0 Hareesh Janakiraman over 6 years ago in reply to Hareesh Janakiraman

Linda,

Any updates?

0 Linda Zhang84708 over 6 years ago in reply to Hareesh Janakiraman

Hello Hareesh,

Customer has found out the issue is caused by their software coding and not related with PLL settings.

Thank you so much for your kind help.

Best Regards,

Linda

C2000 microcontrollers forum