New MPC5200 Eratta/ATA Bugs

Eric N. Johnson (ACD) ejohnson at
Tue Apr 26 05:22:56 EST 2005

Freescale just realeased a new version of the eratta (hardware bugs) 
document for the MPC5200.  It was posted last week, and adds some pretty 
significant problems to the FEC Ethernet and IDE/ATA sections.

Specifically, I'm wonder if Eratta ID 485 may be the cause of some of the 
IDE issues we've been attributing to Bestcomm:

  "During the concurrent access of ATA DMA READ and PCI or LPC the
   ATA_ISOLATION signal can be incorrectly driven when ATA is paused."

Unfortunately, their proposed workaround isn't appropriate for many 
cases.  They suggest that you not use "ATA_ISOLATION" and connect the ATA 
device directly to the LP bus without any buffering.  This could lead to 
serious bus integrity issues, especially if the ATA device is connected by 
a ribbon cable.

Eric Johnson, Electrical Engineer
Advanced Communication Design
   7901 12th Avenue South
   Bloomington, MN 55425
Ph: 952-854-4000  Fax: 952-854-5774

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