http://forums.leaflabs.com/topic.php?id=1161 A place to share, learn, and grow... en-US Fri, 22 Jan 2016 00:27:52 +0000 http://bbpress.org/?v=1.0.2 q http://forums.leaflabs.com/search.php http://forums.leaflabs.com/topic.php?id=1161#post-7124 Wed, 09 Nov 2011 10:42:39 +0000 joegtp 7124@http://forums.leaflabs.com/ <p>I'm trying to talk to a VS1053 chip (<a href="http://www.sparkfun.com/products/9943" rel="nofollow">http://www.sparkfun.com/products/9943</a>) and I'm having problems changing the speed of the SPI port after I issue a couple commands to change the clock multiplier. Here is an example of what I'm doing...</p> <pre><code>myspi.begin(SPI_281_250KHZ, MSBFIRST, SPI_MODE_0); // setup the clock multiplier to allow faster communications myspi.transfer(...); myspi.begin(SPI_2_25MHZ, MSBFIRST, SPI_MODE_0); myspi.transfer(...); // &lt;-- this line fails to bring back meaningful data</code></pre> <p>I was thinking that I just wasn't configuring the clock multiplier correctly but then I tried calling begin with the same slower clock (SPI_281_250KHZ) and it still fails. If I comment out the second begin it works fine. I also tried calling "end" before the second "begin" and that didn't work either.</p> <p>So I left the line commented out (in a working state). I then started to work on my SDCard code which uses a different SPI port and ran across the same problem. I start the SPI bus at one speed, do some initialization and then try to increase the speed. Same behavior as before. If I comment out the second "begin" it works.</p> <p>The problem I'm having now is that I really need to increase the speed of the SPI because it's not keeping up with the MP3s I'm trying to send it.</p> <p>What is "begin" doing to the SPI bus? Is there something special I need to do when changing the SPI clock speed? </p>