[alsa-devel] About iMX6SL sign extension of SSI Receive Configuration Register (SSIx_SRCR)

[Xuebing Wang]

Hi Nicolin and community,

iMX6SL reference manual section "48.9.8 SSI Receive Configuration 
Register (SSIx_SRCR)" says about sign extension.

Below is a quote from iMX6SL reference manual:
-------------------------------------------------------------
Receive Data Extension. This control bit allows SSI to store the 
received data word in sign extended form.
This bit affects data storage only in case received data is LSB aligned 
(SRCR[9]=1)

0 OFF — Sign extension turned off.
1 ON — Sign extension turned on.
-------------------------------------------------------------

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.
-- Note: SRCR[9] is 1.

Any suggestions? Thanks.

-- 
Xuebing