Stan Chernikov

Flash Address Fetch Speculation bug migrated from MCF5223x to MCF5225x?

Discussion created by Stan Chernikov on Jun 19, 2010
Latest reply on Jun 22, 2010 by Stan Chernikov

Just now I discovered a strange bug in MCF52259. My program would generate a processor exception which can be avoided when single-stepping through the offending code with the debugger. As soon as I disabled Flash Address Fetch Speculation (bit 6 in FLASHBAR), the bug disappeared.

This is exactly the scenario I went through with the MCF52235. The MCF52235 has a published errata document which documents the bug in silicon and promises to fix it in a future revision. I was hoping this bug would not show up in the MCF52259, but it appears it does. Unfortunately, there is no errata document to be found for the MCF52259 on the Freescale website.

I'm comfortable with keeping Address Fetch Speculation disabled. This is just a warning for everyone interested...