--- a/target-utils/c139explore/dac.c	Wed Oct 26 01:53:12 2016 +0000
+++ b/target-utils/c139explore/dac.c	Wed Oct 26 01:59:32 2016 +0000
@@ -29,3 +29,27 @@
 	}
 	abb_reg_write(AUXDAC, val);
 }
+
+void
+cmd_vibe(argbulk)
+	char *argbulk;
+{
+	char *argv[2];
+	u32 val;
+	int c;
+
+	if (parse_args(argbulk, 1, 1, argv, 0) < 0)
+		return;
+	val = strtoul(argv[0], 0, 0);
+	if (val > 0x3FF) {
+		printf("ERROR: argument out of range\n");
+		return;
+	}
+	abb_reg_write(AUXDAC, val);
+	for (;;) {
+		c = serial_in_poll();
+		if (c >= 0)
+			break;
+	}
+	abb_reg_write(AUXDAC, 0);
+}