[sdiy] dsPIC with on-chip audio DACs

[Eric Brombaugh]

On Jul 5, 2008, at 2:15 PM, Tim Ressel wrote:

> Could you describe your development environment?

In this case (and several others in the past) I'm just using a  
solderless breadboard with appropriate regulators, decoupling caps,  
etc. I've got a genuine Microchip ICD2 programming pod (I tried the  
less expensive Olimex version but had problems getting it to work on  
the newer dsPIC33F parts) and some home-made adapter cables to go from  
the RJ45 connector on the ICD2to a 0.1" header that fits into the  
breadboard. Despite what others have said about solderless breadboards  
(ref Harry's "board of pain" comments), if you know the limitations up  
front they can be helpful. I've even gotten crystal oscillators  
working on them. Just be aware of all the parasitics and contact  
resistance/noise issues and you won't be surprised.

For coding I use MPLAB (v8.10 now) which is free from Microchip's  
website. I've been programming in pure assembly, but I'm looking at  
their C compiler - I'm pretty fluent in C, but for DSP chips it can  
sometimes be a bit of a compromise because the language doesn't  
natively support a lot of the highly efficient data structures and CPU  
instructions. Microchip's version has lots of built-in and inline  
functions that invoke their DSP extensions though, so this may work  
out well - time will tell.

Once I've gotten a project running I'll often transfer the hardware to  
perfboard for further development. SMD parts typically go onto some  
sort of adapter to break them out to 0.1" spacing. I've recently  
started to do PCB designs using the gEDA tools though, and this has  
been an awakening. SMD is now a lot more feasible, and the end result  
is very nice looking.

Eric