From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Xuebing Wang <xbing6@gmail.com>
Cc: alsa-devel@alsa-project.org,
niranjan Patil <Niranjan.Patil@infocus.com>,
markus.lindroth@limesaudio.com,
richard Jiang <Richard.Jiang@infocus.com>
Subject: Re: About iMX6SL sign extension of SSI Receive Configuration Register (SSIx_SRCR)
Date: Mon, 9 Mar 2015 19:33:03 -0700 [thread overview]
Message-ID: <20150310023302.GA1384@Asurada-GSX> (raw)
In-Reply-To: <54FD634E.8040007@gmail.com>
On Mon, Mar 09, 2015 at 05:09:34PM +0800, Xuebing Wang wrote:
> After I receive data (in the format of S16_LE) from SSI/I2S, I got data like
> 0x7FFF or 0x77d2. Are they supposed to be 0xFFFF or 0xF7d2?
>
> After setting bit 10 (RXEXT) of SSIx_SRCR, I still get 0x7FFF or 0x77d2.
I don't have much detail information on it. But what I see a sign
extension should only happen during some procedures like converting
a 16-bit signed number to a 32-bit signed number. For example, the
original number is 0x8000 (16-bit), then the result should be a 32-
bit 0xFFFF8000.
However, you are still using 16-bit format and the sample data you
provided looks like positive numbers.
You might need to read a 32-bit result from the Receive FIFO so as
to get a 32-bit sign extended data.
prev parent reply other threads:[~2015-03-10 2:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-09 9:09 About iMX6SL sign extension of SSI Receive Configuration Register (SSIx_SRCR) Xuebing Wang
2015-03-10 2:33 ` Nicolin Chen [this message]
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