Microcontroller; any suggestions?

Why do you explicitly need ethernet ..? ADC/DAC below 10 kHz is avail on many MCUs these days afaik.

What communications range do you need?, speed?, accurency?, reliability?

SPI-Ethernet:

AVR/ATtiny15 A/D, PWM Use PWM to make D/A with delta sigma?

(I would welcome other ppls opinion on these choices..)

I wanted to make a small "IP-phone" for fun. The "phone" will need a ADC/DAC to record/replay speech, and I want to use it on an Ethernet. So what I am looking for is a microcontroller wich can get the job done without any external ic's.

And, yes, I know that it would be a lot easier just to use my PC for this task, but again, this "phone" something I want to make for fun...

Dont pic (no pun intended) out a microcontroller for just one project. There is a large learning curve for any of them; also, you need to get a development set up.

Choose one you think is the most generally useful - it will pay off in the long run.

Luhan

Be sure the publish the results when you are done. I have almost 40 years design experience and would think twice about trying this myself.

Luhan

"Luhan"

Maybe I am a bit optimistic? But why do you mean I should "think twice"; is this a bigger task than I should be able to handle as a hobby-project? I'm thankful for any input; I am not a pro like you...

I guess implementing the VoIP stack completly in a MCU might be a challenge. But if your willing to shave your spec down a bit it might just work. Setup two software loops possible triggered by external oscillator (irq on logic level change). Collect data under X seconds. Then have it transmitted. And in the other loop for every packet received set every byte to the pwm correspondingly.

If your willing to go fpga instead the challenge might be easier ;)

Well, with this:

(or similar: ) and some delta-sigma (sigma-delta?) on the same chip, it actually sounds doable. ;-)

Cheers! Rich

Something like this?

found on:

Good Luck! Rich

So, speaking of TCP/IP on an fpga, if someone did that, what would be the recommended interface to, say, cat5?

Thanks, Rich

You got to have a PHY (like Intel LXT972M) which essentially translates between 4 bits LVTTL and baseband ethernet. After the PHY comes 1:1 signaltransformer and various passive components.

However I suspect it's possible to interface 10 Mbps FD with an electrical hack useing LVTTL I/O's. Not verified thoe. It would however be very touchy to any mishaps, but cheap! ;)

And the PHY needs a 25 MHz 50 ppm crystal.

You're not likely to find such a combination - relatively few micros with Ethernet have an ADC (high speed digital and good analogue don't go well together in the same device), and few micros of any kind have a DAC. However, a Coldfire 52233 has a 100 MBit Ethernet, including the PHY, and 8 channels of ADC. The PWM timers might be good enough resolution for your DAC outputs - otherwise you want a SPI bus DAC.