RE: [ECOS] Peculiar Register Write problem

["Trenton D. Adams" <tadams at extremeeng dot com>]

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)
> 
>