+// Topaz command set:
+#define TOPAZ_REQA 0x26 // Request
+#define TOPAZ_WUPA 0x52 // WakeUp
+#define TOPAZ_RID 0x78 // Read ID
+#define TOPAZ_RALL 0x00 // Read All (all bytes)
+#define TOPAZ_READ 0x01 // Read (a single byte)
+#define TOPAZ_WRITE_E 0x53 // Write-with-erase (a single byte)
+#define TOPAZ_WRITE_NE 0x1a // Write-no-erase (a single byte)