Re: Re: [sdiy] Sound synthesis with microcontrollers

[Roman]

---- Wiadomość Oryginalna ----
Od: jbv <jbv.silences at club-internet.fr>


>As for soldering, I guess that some of you guys do that daily, but
>I just can't imagine designing / soldering around a 240 pins MQFP...

it's actually easier than soldering 120 pins DIP if there would be something like that. This technique was described here few times. Basically you smear solder with soldering iron along pins flooded in flux.

>And my core design shouldn't include more than 4 or 5 chips...

with DSP it wouldn't be that many either

>>http://www.sowa.synth.net/evm2181.html
>>
>
>Looks interesting, but any idea how much this costs ?And one more 

100EUR

>question :
>once I've written and debugged my code on
>my eval. board, what if I want to cook my own little module to implement
>it ? How do I switch from this board to my own circuitry ?

simple - you copy it without circuitry you don't need, plus some stuff you'll need, like EPROM with firmware. You could even get empty PCB of evm2181 to start with.
Or you can use smaller DSP, like old ADSP2115, 2104 etc, that go for about 20$ AFAIR and come in PLCC package, meaning only 68 socket pins to solder. What else DSP needs is EPROM and ADC/DAC. If it needs MIDI, I'd use small micro, like PIC, to handle MIDI traffic and talking to DSP in its language, as DSPs are horrible in such stuff.

>But IMHO it actually depends on what I'm after...
>For instance, if I want to implement a simple vco or vcf module,
>the XA with its (rather) fast multiply-accumulate and
>onboard ADCs / UART / RAM etc. can do the job easier & cheaper...

Right. If you want single standalone module, small micros are justified. Unbeatable comparing to DSPs, that don't have onboard ADCs/UARTs at this price range.

Roman