S12 / MagniV Microcontrollers中的主题 Re: PLL in HCS12X Board

PLL in HCS12X Board

kayji — Wed, 22 Jun 2011 14:16:49 GMT

Does anybody know where the xtal port is in DEMOMC9S12XEP BOARD? As i know to use a PLL Clock, xtal port should be connected with appropriate capacitors and resistors but my board doesn't have. I've already checked schmetic, manual.

Re: PLL in HCS12X Board

kef — Wed, 22 Jun 2011 14:37:19 GMT

Do you mean PLL filter components connected to XFC pin like on older S12XD and S12XA? S12XE has no XFC pin and PLL filter components are built in into the chip.

Re: PLL in HCS12X Board

kayji — Wed, 22 Jun 2011 15:53:27 GMT

yes I meant that. So you mean I just need to make the right codes to use PLL, right? with no capacitors, any resistors.

i'm trying to do but still it is not working yet so i suspected that some components are needed to use that.

then can i ask one more thing? How much arrange of frequency can i use for bus clock? My friend said 50MHZ bus

clock changed by PLL is limit. i'm not sure he is right.

Re: PLL in HCS12X Board

kef — Wed, 22 Jun 2011 17:29:28 GMT

S12XE uses different PLL initialization code, so your old routines for S12XD most likely won't work.

Yes, S12XE bus clock tops at 50MHz. Check electrical specs in S12XE datasheet.