RE: RE: Quickstart on MPC555 with GNU C

Hi Dobbin,

 

1) What is a basic operation? 

2) Why would a basic operation crash the processor?

3) I didn't write the code, it came with the Motorola quickstart package,
shouldn't it be safe to assume that code that Motorola writes for their own
processor should work okay? Why would it crash the processor?

4) The programming environments manual for the MPC555 explained all about
writing the PLPRCR. It didn't say anything that I saw about being careful
about when or how one writes the register for risk of crashing the
processor. Did you see some documentation that explained that?

 

Thanks,

 

Dave

 

 

 

 

  _____  

From: [email protected] [mailto:[email protected]] On Behalf Of
Dobbin Allan-r11834
Sent: Tuesday, April 19, 2005 6:28 AM
To: '[email protected]'
Subject: RE: [MPC500] RE: Quickstart on MPC555 with GNU C

 

See previous messages #2661 and #2708.

Sounds like you are looking for flaws in the processor before reading any
documentation.  Setting the system clock using the PLPRCR[MF] is a basic
operation.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
David Eicher
Sent: Tuesday, April 19, 2005 8:45 AM
To: [email protected]
Subject: [MPC500] RE: Quickstart on MPC555 with GNU C



In the appconfig.h file (generated by the configuration tool) there are
comments about the change in divide ratio for the PLL. It is switching the
board to low power mode and dropping the CPU clock from 40Mhz to 20Mhz. I
just commented out the #define for now to remove this code since it cause
the machine to crash. I'll study that problem later, will let it run at
40Mhz for now.



Regards,



Dave





  _____  

From: David Eicher [mailto:[email protected]] 
Sent: Monday, April 18, 2005 7:09 PM
To: '[email protected]'
Subject: Quickstart on MPC555 with GNU C



Hello list,



After getting some help fixing the initialization of pointers, my code is
executing into the 5xx_board_init.c stuff. The code writes to the PLPRCR
into the MF bits, I believe it is to change the Phase lock loop divider
ratio. The computer loses it's mind right there, it crashes and will not do
anything after that. There is a loop in the code after this write to the
register that is suppose to test the SPLS bit and wait there until the loop
locks again. 



Are there any known problems with writing to this register on the MPC555? I
suppose I'll have to comment this out for now so I can debug the remainder
of the code but will eventually need to know what to do with this code.



I did talk to a coworker at work who has had some experience with this
processor and he said it does have quite a few issues, the MPC565 is a much
more mature part, according to him. Maybe this is one of the issues?



Thanks,



Dave





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