Lower Cost AOUT

[fabioldr]

Hi,

I'm thinking about creating a new low cost AOUT module that uses the low-cost Microchip MCP4922 for those (like me) who want fewer CV outputs, but still want precision to drive VCOs

Advantages:

- Comes in DIP package

- Low cost: US$ 3,16 at mouser, R$ 12 in Brazil :-)

- 12 bits resolution

- SPI Interface

Disadvantages:

- 4,5 uS Latency (i don't know if that's bad actually! the TLV5630IDW from AOUT_NG has 3uS in slow mode)

- Only two DACs

My question:

what do I have to change in MIOS in order to make the CORE module communicate with this new AOUT?

[seppoman]

Hi,

first, a "user project" is defined as a project that is aready started and progressed to some extent, and has some documentation online on the Wiki. So this thread needs to be moved to the Design Concepts section of the forum :)

Creating a low cost AOUT that is easier to build and better than the AOUT_LC is a nice idea. The MCP DACs would probably be suitable for that. But I'd suggest using the MCP4822 instead - it's only DIP8 and has an integrated voltage reference. for the 4922 you'd need to add an external reference which makes the module more expensive and more complicated (good references cost a few dollars and are mostly available as small SMD parts). Other than that, the MCP4822/4922's specs should be ok for such a project. Setup time/latency is no problem here (actually, slower signals might even smoothe the CV a bit which is desirable).

For communication, you'll need to write your own MIOS driver that supports the DAC's SPI protocol. You can find information in the part's datasheet. It's a quite simple protocol. Perhaps it's a good starting point to take a look into the AOUT_LC's and AOUT_NG's MIOS driver while reading the TLV5630's datasheet.

Good luck :)

S