From: Craig H. <cr...@gu...> - 2005-08-24 22:24:54
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On Aug 24, 2005, at 10:52 AM, Doug Sutherland wrote: > The interesting thing about these dual codecs is that the HiFi > codec interface > (I2S or AC97) data can be sent over the PCM (bluetooth) and vice > versa. This > allows the host to do things like play mp3 but also deal with phone > calls over > the PCM interface. The wolfson codecs also have mixing capability, > each codec > has a PGA (programmable gain amplifier), and they have ALC > (automatic level > control) capability for recording incoming calls, and sidetone path > so you can > hear what you say on the phone etc. The problem wrt gumstix is that > bluetooth > is on the CPU module, but there is only one audio port exposed on > the connector. > So to connect a dual codec, either both bluetooth and audio codec > would have > to be on the CPU module, or the connector would have to have both > the Hifi > (AC97/I2S) and Voice (PCM) signals (allowing both to be external). > My plan is > to try an external bluetooth module and external dual audio codec. Well, the connector *would* have both sets of signals. The AC97 as is, and the PCM data would go over one of the sets of SSP lines (probably the SSP rather than the NSSP). That way you can use the gumstix as something like a fancy answering machine w/out the audiostix mk2 (by just reading/writing the PCM via SSP from the PXA), or you can use it as a computer-assisted headset by using AC97 to tell the audiostix mk2 what to do with the audio. C |