Add gps, debug dongle support and pressure alt tables

GPS also pulled in serial support. The altitude tables take raw 11-bit
pressure sample numbers and convert them to standard pressure altitude
values.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/gps-cksum b/gps-cksum
new file mode 100755
index 00000000..a08153bf
--- /dev/null
+++ b/gps-cksum
@@ -0,0 +1,17 @@
+#!/usr/bin/env nickle
+
+int checksum(string a)
+{
+	int	c = 0;
+	for (int i = 0; i < String::length(a); i++)
+		c ^= a[i];
+	return c;
+}
+
+void main()
+{
+	for (int i = 1; i < dim(argv); i++)
+		printf ("$%s*%02x\n", argv[i], checksum(argv[i]));
+}
+
+main();