Initial commit.

include/ms5611_crc.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+
+//  MS5611 factory PROM CRC-4 (datasheet p.13, algorithm specified in AN520).
+//  `prom` holds the 8 PROM words as read from the part; word 7 carries the
+//  stored CRC in its low nibble. The array is restored before returning.
+//
+//  Deliberately free of Arduino headers so it can be built and tested on the
+//  host against the AN520 reference vector.
+bool ms5611PromCrcOk(uint16_t prom[8]);