[ECOS] Changing flash wait state on SAM7

Andrew Lunn andrew@lunn.ch
Mon Apr 7 23:14:00 GMT 2008

On Mon, Apr 07, 2008 at 01:34:58PM -0300, Davies, Greg wrote:
> I've been having some strange memory issues that I've been talking about
> in the "eCos causing something.. Maybe?" thread. Basically I was seeing
> random values when I did a dump of any section of memory. The BDI folks
> suggested I change the flash wait state. I did this and the problem went
> away. 

Something else to check. I found that my JTAG device will download a
little bit of code which starts the PLL running and then swaps from
slow clock to pll clock. This allows it to download code faster etc.
It could be that it is setting a really fast clock which does require
more wait states. So when you start eCos using BDI it is running on a
fast PLL clock, not slow clock, or a medium speed PLL. The first thing
the startup code does is reprogram the wait states, which could get it
into trouble.

See if you have any configuration options for BDI. Another option
would be to change hal_platform_setup to only change the wait states
once the CPU is running on slow clock.


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