I'd like to find a simple single chip, much like the USB-fifo chips that are available, but on 100mbit ethernet. Ideally, this would be able to do little more than listen for packets on its address, and pass them to a FIFO for use locally. It'd be nice if this could do DHCP to discover its IP address. Even more ideal would be if it had an A/D to do 16 bit stereo sound.
I assume such doesn't exist. What's the closest that's out there?
Not quite what you're looking for, but might be of interest -
Basically, cheap(ish) easily programmable low power multi-speaker sound throughout the house. There is the option of a hundred wires and soundcards/mixers, but that gets bulky.
Thanks, will have a browse.
I take it you already have a LAN?
In case it needs extending: there's a review of MicroLink dLAN Audio in Elektor this month. It does audio and ethernet over the mains wiring:
I do. I'd also like to be able to put the link over 802.11g in some parts.
Thanks, but I'd like at least 8 stereo channels, for a total of around
15 megabits/sec. I'd rather not try to get this over the mains, when there is no need.
NetARMs (for easy development)... Samsung's got processors with integrated MAC (and maybe PHY) also... And there's probably lots of others. Google is your friend!
/A
Freescale claims their new MC9S12NE64 is the first single-chip 100Mb processor with integrated PHY. There are many others with integrated
100Mb MAC, but they require an external PHY chip. However, you hardly need 100Mb (or really even Ethernet)... 10Mb or other technologies will expand your options.FYI, G.711 CODEC (uncompressed mono channel) uses 8,000 8-bit samples per second. At 16 channels (8 stereo) that's 1Mbps, and that's if you use a broadcast (preferably multicast) technique. If you use unicasting instead (and presumably an Ethernet switch instead of hub), the nodes will only need 128Kbps each. Either way, at these speeds you have more transport options to choose from.
Ethernet, especially integrated and 100Mb will also put you into a much higher price range for the overall kit. I'd suggest looking into the newer short-range "low speed" wireless stuff like Zigbee, or powerline as someone else suggested; even serial bus might be practical - eliminating the Ethernet interface (and especially an IP stack) will greatly simplify the development.
FWIW, Richard
So, your CODEC is 1Mbps per audio channel? Good grief.
My point was, I think your math is off. 10Mb Ethernet could probably handle 100 parallel channels of uncompressed audio...
uncompressed 44.1khz 16 bit stereo requires 1.4mbps. 10mb ethernet could have a hard time carying 100 such streams.
100Mb would be nice. It'd plug into the existing network, and 'just work'. 10Mb would use 50% of the network bandwidth on only 4 or 5 streams.
Thanks all. Thinking about this. I can probably get away with a suitable laptop motherboard ($40 on ebay) and a USB sound chip or two.
And lose the possibility of selling a finished unit of course, which is a pity.
Not if you use a network switch instead of a hub. The central unit providing the streams is probably a PC. Connect this with 100Mbit to a switch. All downstream devices can be 10Mbit. The switch will distribute the 100Mbit link over the 10Mbit devices.
In my original message was "Even nicer would be if it could do 44.1Khz stereo" which while not quite specifying CD quality implies it, or maybe I could have been clearer.
No-one mentioned CD quality audio until just then.
Ken
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