altos: Software implemenation of CC1111 radio encoding

[fw/altos] / src / util / make-whiten

diff --git a/src/util/make-whiten b/src/util/make-whiten
new file mode 100644 (file)
index 0000000..d68a02a
--- /dev/null
+++ b/src/util/make-whiten
@@ -0,0 +1,37 @@
+/*
+ * Copyright © 2012 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+/* Generate the data whitening array used by the CC11* radios */
+
+int pn9 = 0x1ff;
+
+void
+pn9_step() {
+       pn9 = (pn9 >> 1) | (((pn9 ^ (pn9 >> 5)) & 1) << 8);
+}
+
+int val()
+{
+       int     ret = pn9 & 0xff;
+
+       for (int i = 0; i < 8; i++)
+               pn9_step();
+       return ret;
+}
+
+for (int i = 0; i < 128; i++)
+       printf (" /* %3d */ 0x%02x,\n", i + 1, val());