MCF548x CLKIN to PLL?

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

MCF548x CLKIN to PLL?

Jump to solution
724 Views
zwilcox
Contributor IV

I'm trying to hook up a crystal to the MCF5484.  

There's a CLKIN line where it looks like the crystal hooks up to.  Usually there's like a CLKOUT or osc_out, xtal_out or something but I'm not seeing that.

This is what I have so far:
pastedImage_1.png

Am I missing something?

Thanks in advance
Zach

Edit:  Here's the full module for the Test, Reset, and Clock portion
pastedImage_1.png

1 Solution
529 Views
TomE
Specialist II

The Data Sheet has a section on the PLL detailing the CLKIN signal in "Table 7. Clock Timing Specifications". The levels and rise time can only be obeyed with an external hybrid oscillator, not a crystal.

In the Reference Manual:

10.1.2  Clocking Overview
The MCF548x requires a clock generated externally to be input to the CLKIN signal.

Tom

View solution in original post

6 Replies
529 Views
miduo
NXP Employee
NXP Employee

Hello,

Actually the M5485EVB is not designed by NXP(Freescale). It was developed by LogicPD. However we had an internal evaluation board which was for internal test. The above schematic is from this board.

530 Views
TomE
Specialist II

The Data Sheet has a section on the PLL detailing the CLKIN signal in "Table 7. Clock Timing Specifications". The levels and rise time can only be obeyed with an external hybrid oscillator, not a crystal.

In the Reference Manual:

10.1.2  Clocking Overview
The MCF548x requires a clock generated externally to be input to the CLKIN signal.

Tom

529 Views
zwilcox
Contributor IV

Ahh ok.  Cool thanks.   I'll need to fix this.  That helps. 

0 Kudos
529 Views
TomE
Specialist II

I've just received email on this thread from you (Zachary) asking for the schematics for the ref board. As of this time the post isn't visible here, so I guess it'll get there before this one does.

Anyway...

On the NXP MCF5485 Page under the "Software and Tools" tab there are two "Reference Board" packages. These contain schematics.

Tom

529 Views
miduo
NXP Employee
NXP Employee

Hello,

Please see our evaluation board for the clock scheme:

pastedImage_1.png

529 Views
zwilcox
Contributor IV

Hey miduo‌!

Would you be able to provide the schematic for the eval board? 
I don't see it listed here MCF5485 Evaluation Board|NXP 

Thanks :smileyhappy:

0 Kudos