--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wh1080_dev.h	Tue Feb 09 13:44:25 2010 +1030
@@ -0,0 +1,123 @@
+/*
+ * WH-1080 data input utility.
+ * This bases on code supplied to me by Steve Woodford.
+ *
+ * Greg Lehey, 16 November 2009
+ *
+ * $Id: wh1080_dev.h,v 1.4 2009/12/08 01:03:12 grog Exp grog $
+ */
+
+#ifdef linux
+/*
+ * I wish I understood linux header files.  This whole thing looks like a mess.
+ * If you can explain it to me, please do.
+ */
+#include <endian.h>
+#include <asm/byteorder.h>
+#define htobe16 __cpu_to_be16
+#define le16toh __le16_to_cpu
+#include <time.h>
+#else
+#include <sys/endian.h>
+#endif
+/*
+ * This file describes the WH-1080 weather station as well as I can understand
+ * it.  The station is not documented, and I've pulled this together from
+ * various source code written by others without access to documentation.
+ */
+
+/* Vendor and product number for WH-1080 */
+#define WH1080_USB_VENDOR               0x1941
+#define WH1080_USB_PRODUCT              0x8021
+
+#define WH1080_PAGE_SIZE             32
+#define WH1080_PAGE_MASK              (~ (WH1080_PAGE_SIZE - 1))
+
+/* Offsets of the first 2 pages */
+#define WH1080_PAGE0                    0
+#define WH1080_PAGE1                    0x20
+/* First archive record appears to start here */
+#define WH1080_FIRST_ARCHIVE            0x100
+/* And the last one must be here */
+#define WH1080_LAST_ARCHIVE            0xfff0
+/* And thus there appear to be this many of them. */
+#define WH1080_ARCHIVE_COUNT            4088
+/* The records swap this often, in seconds */
+#define WH1080_ARCHIVE_INTERVAL         1800
+/* Size of archive record */
+#define WH1080_ARCHIVE_RECORD_SIZE      16
+
+/* Descriptor stuff.  I'm not sure what this is all about. XXX */
+#define WH1080_DESCRIPTOR1_SIZE        18
+#define WH1080_DESCRIPTOR2_SIZE        9
+/*
+ * Steve Woodford has:
+ * #define WH1080_DESCRIPTOR3_SIZE        34
+ * #define WH1080_DESCRIPTOR34_SIZE       0x74
+ */
+#define WH1080_DESCRIPTOR3_SIZE        34
+#define WH1080_DESCRIPTOR34_SIZE       0x74
+
+/*
+ * The device appears to have its data stored in pages of 32 bytes.  I have very
+ * little information beyond what I've gleaned from other people's code, so some
+ * of this looks very strange.
+ *
+ * The following structures define what we know of the first two pages.
+ */
+struct wh1080_page0
+{
+  uint64_t magic;                               /* one of apparently 2 different magic numbers */
+  uint64_t magic2;
+  char mumble [14];
+  uint16_t current_page;                        /* byte offset of current readings */
+};
+
+/* These seem to be alternate values.  No idea why. */
+#if BYTE_ORDER == LITTLE_ENDIAN
+/* XXX find out which endian this is */
+#define WH1080_PAGE0_MAGIC1A              0xffffffffffffaa55ull
+#define WH1080_PAGE0_MAGIC1B              0xffffffffffaaaa55ull
+#define WH1080_PAGE0_MAGIC2               0xffffffffffffffffull
+#else
+#define WH1080_PAGE0_MAGIC1A              0x55aaffffffffffffull
+#define WH1080_PAGE0_MAGIC1B              0x55aaaaffffffffffull
+#define WH1080_PAGE0_MAGIC2               0xffffffffffffffffull
+#endif
+/* It's not clear what the purpose of page 1 is.  One pressure reading comes with the current data. */
+struct wh1080_page1
+{
+  uint16_t rel_pressure;                        /* hPa / 10 */
+  uint16_t abs_pressure;                        /* hPa / 10 */
+  char mumble1 [28];
+};
+
+/*
+ * At least current weather data looks like this.  This record should be exactly
+ * 16 bytes long.
+ */
+struct wh1080_readings
+{                                               /* offset: */
+  uint8_t last_save_mins;                       /* 0: last save minutes (?) */
+  uint8_t inside_humidity;                      /* 1: humidity in percent */
+  int16_t inside_temp;                          /* 2: inside temperature, °C/10 */
+  uint8_t outside_humidity;                     /* 4: humidity in percent */
+  int16_t outside_temp;                         /* 5: outside temperature, °C/10 */
+  uint16_t pressure;                            /* 7: absolute pressure, hPa / 10 */
+  uint8_t wind_speed;                           /* 9: wind speed in m/s/10, up to 25.5 m/s */
+  uint8_t wind_gust;                            /* 10: wind gust speed in m/s/10, up to 25.5 m/s */
+  char mumble1;                                 /* 11: apparently unused byte */
+  /*
+   * wind direction is a number between 0 and 15, repesenting increments of
+   * 22.5°.  It may also have the value 0x80 if there's no wind at all.
+   */
+  uint8_t wind_direction;                       /* 12: */
+  /*
+   * Rainfall is measured in units of 0.3 mm, and the value returned is a
+   * counter.  There's only real rainfall if the value returned here is
+   * different from the previous reading.
+   */
+  uint16_t rain;                                /* 13: */
+  char mumble2;                                 /* 15: pad to 16 bytes */
+} __packed;
+