Example program to do a frequency sweep on the speaker

Fork of app-shield-speaker by Chris Styles

Revision:
5:aba9347842e0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os.lib	Tue Sep 19 19:29:12 2017 +0000
@@ -0,0 +1,1 @@
+https://github.com/armmbed/mbed-os/#ca661f9d28526ca8f874b05432493a489c9671ea