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RE: Peculiar Register Write problem
- To: "'Lewin A.R.W. Edwards'" <larwe at larwe dot com>,"'eCos discussion'" <ecos-discuss at sources dot redhat dot com>
- Subject: RE: [ECOS] Peculiar Register Write problem
- From: "Trenton D. Adams" <tadams at extremeeng dot com>
- Date: Wed, 27 Jun 2001 09:48:37 -0600
- Organization: Extreme Engineering
Ok, I found something very interesting. I did a delay before my code
that wasn't working, and it now works. There is no where in the
documentation that talks about needing a delay. Why would this be
required?
> -----Original Message-----
> From: Lewin A.R.W. Edwards [mailto:larwe@larwe.com]
> Sent: Wednesday, June 27, 2001 9:19 AM
> To: Trenton D. Adams; 'eCos discussion'
> Subject: Re: [ECOS] Peculiar Register Write problem
>
>
>
> >This is the code for initializing the CL-PS6700 PCMCIA controller.
> >Everything from PCCIRR1 on does not happen. I've put this
> code inside
> >a
>
> [...]
>
> >If I put
> >in those 4 lines after a call to cf_init (), the registers do get set
>
> So we can infer that your init code as posted is not
> complete, and that it
> relies on some other register's state being intialized by
> cf_init(). Look
> at the source for cf_init() and see what registers it
> initializes. Cut and
> paste into your code until the registers become properly writable.
>
> Cirrus's other EDBs use GPIO pins to drive chip select
> signals on various
> hardware. Check in particular that you're setting up the data
> direction
> register for the GPIO pins correctly, I think this is a
> likely culprit for
> your problem. (Just copy the value eCos uses for the time
> being, once you
> develop your own board you could modify it where necessary.
> But whatever
> value eCos uses will be sensible - presumably <g> - for the
> Cirrus board).
>
>
> -- Lewin A.R.W. Edwards
> Embedded Engineer, Digi-Frame Inc.
> Work: http://www.digi-frame.com/
> Tel (914) 937-4090 9am-6:30pm M-F ET
> Personal: http://www.larwe.com/ http://www.zws.com/
>
> "Far better it is to dare mighty things, to win glorious
> triumphs, even
> though checkered by failure, than to rank with those poor spirits who
> neither enjoy much nor suffer much, because they live in the
> gray twilight
> that knows not victory nor defeat."
> (Theodore Roosevelt)
>
>