Subject: Re: minor ad1848 problems
To: None <jabaker@grail.cba.csuohio.edu>
From: Mike Long <mike.long@analog.com>
List: tech-kern
Date: 07/06/1996 19:02:22
>Date: Wed, 3 Jul 1996 12:01:07 -0400
>From: jason <jabaker@grail.cba.csuohio.edu>
>
>I hope I am in time to get this fixed for 1.2.  There are two typos in
>the ad1848 audio code.  The first is harmless, but the second prevents
>recording on an ad1848k.
>
>CAPTURE_UPPER != PLAYBACK_UPPER, but since netbsd does not do pio the
>question is moot.
>
>AUTO_CAL_ENABLE is in the interface config register.  Trying to set
>AUTO_CAL_ENABLE in the clock and data register selects a
>non-existent sample rate and really confuses the ad1848k.  As long as
>the clock and data format register is in this confused state, the
>interface config register can't be set, and the chip can't be made to
>use the single dma channel for record as well as playback.

I have checked both of Jason's changes against my 1848 data sheet, and
he is correct in both cases.  So I second his recommendations.

FYI for anyone who wants to work on this code:  ADI datasheets are
available from <URL:http://www.analog.com>.  The AD1848 data sheet is
not online because it's too old, but there is one for its successor
the AD1845: <URL:http://www.analog.com/adibin/locate?AD1845>.  It's in
Adobe Acrobat format (.pdf), so you'll have to get a reader working on
your machine.
-- 
Mike Long <mike.long@analog.com>     <URL:http://www.shore.net/~mikel>
VLSI Design Engineer         finger mikel@shore.net for PGP public key
Analog Devices, CPD Division          CCBF225E7D3F7ECB2C8F7ABB15D9BE7B
Norwood, MA 02062 USA       (eq (opinion 'ADI) (opinion 'mike)) -> nil