Kako povezati I2S (PCM) digital audio interface sa racunarom

[ruvic]

Pozdrav svima,

pokusavam da skontam kako da povezem Motorola G24L (GSM Module) sa racunarom.

Mozda neko od vas ima ideju ili moze da pomogne. G24 ima analogni i digitalni audio interface. Analogni me ne interesuje jer zelim digitalno iz racunara da saljem i primam audio(voice).

Pretrazio sam cijeli Internet, razmatrao TI PCM2706 i slicne, ali nisam skontao. Meni treba bidirekcioni prenos glasa.

G24 nudi sljedeci interface:

Digital Audio Interface
The G24-L digital audio interface is a serial Pulse Code Modulation (PCM) bus, which uses
linear 2's compliment coding. G24-L is the PCM bus master, supplying the clock and sync signals
to the application.
The G24-L digital interface is a 4 signal PCM bus, which includes a bit clock output signal for the
bus timing, a frame sync output signal for audio sampling timing, and serial data input and output
signals.
The PCM bus signal's configuration is:
• PCM_CLK - 520 kHz serial clock
• PCM_FS - 8 kHz bit-wide frame-sync
• PCM_DOUT - 13-bit linear audio data output
• PCM_DIN - 13-bit linear audio data input
The analog audio is sampled at an 8 kHz rate and converted to linear 13-bit serial PCM audio
data. The serial data is transferred on the PCM bus in 16-bit word format, which includes 13
sampled data bits, and 3 added zero value bits.
The 16-bit serial data is transferred in both directions after each sync signal's falling edge. The
sync signal pulse duration is one clock period, after which the serial data is transferred in both
directions for 16 consecutive clock periods.
Following the 16-bit data transfer, the serial input and output data signals inactivate until the next
sync pulse, which occurs every 125 μS (8 kHz). It is recommended the serial data signals will be
High-Z during the inactive period.

Hvala Puno,
Alen Ruvic

[pedja089]

Naslici ti je prikaz signala, zakaci pinove na parelelni port. Za kontrolu porta pogledaj malo io.dll.
Imas idobro objasnjeno na milan.milanovic.org/skola
A onda ti ostaje dalje samo ispratiti softverski te protokole.
A da ne spominjem koliki ce problem biti pretvaranje analognog signala u digitalni, i slanje podataka...
Mislim da je mnogo jednostavnije, i prakticnije koristiti analogne ulaze i izlaze i na modemu i na racunaru...

[ruvic]

Hi,

hvala puno na odgovoru. Moram jos dosta toga procitati o paralelnom portu, ali evo vec sada par pitanja:

1. Posto meni treba bidirekciona komunikacija (u isto vrijeme se salje i prima glas - ako su sagovornici nekulturni ) vjerujem da savjetujete EPP nacin rada? Takodjer PCM full-duplex vjerovatno zahtjeva 64 kbps u jednom pravcu, sto bi bilo 128 kbps u oba pravca u isto vrijeme. EPP to moze podrzati?

2. Vjerovatno ce mi trebati neki vid "tri-state serial to parallel conversion register" ili da ubacim neki "bus buffer chip"?

3. Ima li neko prikladnih sema slucajno?

LP,
Alen Ruvic

[pedja089]

Na paralelnom portu postoje i ulazi, tj status port. Za brzinu porta proveri, mislim da moze toliko...Ali cisto sumljam da ce softver stici sve da isprati...