[alsa-devel] Digital Audio Multiplexer of the i.MX27 processor

Juergen Beisert jbe at pengutronix.de
Tue May 27 17:13:49 CEST 2008


does anybody understand the DAM unit in the i.MX27 processor?
This routing device drivers me crazy, as I do not understand how to route 
clocks, syncs and the data signals of my internal i2s unit to the processor's 
All I can see is, when I enable the internal SSI unit in i2s mode, the DMA 
unit transfers some data into it, but the SSI unit does not shift it out. So 
everything stops, the DMA timeouts and I cannot hear anything. I can see the 
external device generates clock and frame signals, but it seems they do not 
reach the internal SSI unit.
Has anybody a working DAM configuration which uses the internal SSI#1 as an 
i2s slave, an external i2s device connected to the SSI#1 pin group of this 
processor which acts as a master (I did not find anything in the manual, how 
the relation between the internal so called port-1 to port-6 at the DAM unit 
and the 4 external SSI1...SSI4 pin groups are). Means the external i2s device 
generates the clock and frame signal and the internal SSI#1 unit in i2s mode 
should use it to send serial sound data to the external device.

Dipl.-Ing. Juergen Beisert | http://www.pengutronix.de
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