VMusic2 and SPI


Senior Member
I'm working on a project using the VMusic2, and a PICAXE-28X1 is (currently) acting as a crude converter between serial and the Texas Instruments linking protocols. I'm using the hardware serial routines on the 28X1.

For the most part this works well, but when receiving larger quantities of data I receive duff data. I assume this is because the TILP is so slow, the receive buffer is overflowing.

I tried to use the VMusic2 over SPI, but I have no idea what that entails so all I'm getting is a constant stream of zeroes from the device. Has anyone got it working over SPI?

I notice in Technical's sample code that VMusic2 pin 6 (CTS) is connected to PICAXE output 0. I've tried setting that high when sending to the TI then setting it low again afterwards, but to be honest I really have no idea what I'm doing or whether that helps in any way whatsoever. :)



Senior Member
I too am desperately trying to find out how I can get the VMUSIC2 to tell the 28X1 what its doing... anyone had any luck doing that??


Technical Support
Staff member
There doesn't seem to be a lot of detail in the Vinculum data sheets on using SPI, or I am looking in the wrong place.

In the "Vinculum Firmware User Manual V2.0 Rev 2.pdf" and the later "... V2.1 Rev 2.pdf" the SPI connections required are shown ( around page 15/18 ). CTS# for serial becomes CS for SPI, so I read that as needing to be an active high signal while communicating with the VMUSIC2.

There are two additional signals, "DATAREQ# and DATAACK# allow for switching between command mode and data mode", but no explanation of how they are used - I'd have expected at least DATAACK# to be an output, but perhaps not.

There's a Vinculum Project Page ( <A href='http://www.vinculum.com/projects.html' Target=_Blank>External Web Link</a> ) which includes example code for using SPI. It's going to be a case of working through that and any other example code you can find on the web which describes it ( <A href='http://forums.parallax.com/forums/default.aspx?f=25&amp;m=159677' Target=_Blank>External Web Link</a> ).

That last example ( see &quot;PRI transfer(read,status,data)&quot; ) shows how data is transferred in and out via SPI, and I imagine that wasn't just guessed at, so if anyone can find the actual Vinculum SPI specification that would be a great help.