+/*
+ * Copyright © 2008 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+sfr at 0x80 P0;
+sfr at 0x90 P1;
+sfr at 0xA0 P2;
+sfr at 0xC6 CLKCON;
+
+sfr at 0xF1 PERCFG;
+sfr at 0xF2 ADCCFG;
+sfr at 0xF3 P0SEL;
+sfr at 0xF4 P1SEL;
+sfr at 0xF5 P2SEL;
+
+sfr at 0xFD P0DIR;
+sfr at 0xFE P1DIR;
+sfr at 0xFF P2DIR;
+sfr at 0x8F P0INP;
+sfr at 0xF6 P1INP;
+sfr at 0xF7 P2INP;
+
+sfr at 0x89 P0IFG;
+sfr at 0x8A P1IFG;
+sfr at 0x8B P2IFG;
+
+#define nop() _asm nop _endasm;
+
+void
+delay (unsigned char n)
+{
+ unsigned char i = 0;
+
+ n <<= 1;
+ while (--n != 0)
+ while (--i != 0)
+ nop();
+}
+
+void
+tone (unsigned char n, unsigned char m)
+{
+ unsigned char i = 0;
+ while (--m != 0) {
+ while (--i != 0) {
+ P2 = 0xff;
+ delay(n);
+ P2 = 0xfe;
+ delay(n);
+ }
+ }
+}
+
+void
+high() {
+ tone(1, 2);
+}
+
+void
+low() {
+ tone(2, 1);
+}
+
+main ()
+{
+ CLKCON = 0;
+ /* Set p1_1 to output */
+ P2DIR = 0x01;
+ P1INP = 0x00;
+ P2INP = 0x00;
+ for (;;) {
+ high();
+ low();
+ }
+}