Report 4: This covers the memory map, fonts, messages and datums names. The memory map of the GPS45 is basicly: FFFFF: 256K ROM C0000: 80000: Display driver? 40000: 10000: 64K RAM 00000: There is still one memory area left to decode as well as all the I/O space. I found a part on the display driver called a D1560TOB display driver. It also has the code 4Z64. It has 48 pins going to the GPS45 and about 180 pins going to the LCD. Its a die attached to a flex circut. The Following letters are in the font tables for the "fancy" fonts where it says "GARMIN GPS 45"... Letter: _ _ _ 0 1 2 4 5 8 9 A C E G I L M N P Q R S T U X # Width: 1 c 6 c 7 9 c a b b c b 9 b 5 9 e c c e c 9 b c d c _ are spaces and # is a diamond. So why are the characters "1289CELQTUX" in the rom? The code that shows this also knows about a GPS 40, 45, 80 and 120. Anyone know what a G80 is? These fonts are 16 bits wide (or 8 bits in the case of 1 or I). They are in the same format as the Arrow used on the "GOTO" screen. This is the list of messages and comments about them. Ones without comments are not used by the G40/45 as far as I know. 0 Can't Change Active WPT The waypoint is selected with the goto function. 2 Start Altitude Change 3 Final Altitude Alert 5 Approaching Getting close to waypoint. 7 Arrival at At waypoint. Not GPS45 Error? 8 Cannot Navigate Locked Route 10 Stored Data was Lost Battery voltage is too low or Mark was pressed on power up. 11 Database Memory Failed 12 No Position No SVs locked 22 Route is Full Too many waypoints in route. 23 Route is not Empty You can't delete a route that has waypoints. 24 Route Waypoint Can't be Deletd You cant delete a waypoint in a route. 25 Route Waypoint was Deleted 26 Received an Invalid WPT 27 Timer Has Expired 28 Transfer has been Completed Upload or download is finished. 29 Vertical Nav Cancelled 30 WPT Memory is Full 31 Already Exists 33 Accuracy has been Degraded 34 Anchor Drag Alarm 35 Battery Power is Low The voltage is too low for the battery. 36 CDI Alarm 37 Leg not Smoothed 38 Memory Battery is Low Your about to loose datapoints unless you get more power soon. 39 Need 2D Altitude You must enter an altitude before it can do a 2D fix. Also if the altitude is negative. 40 No DGPS Position DGPS is selected but there is no fix. 41 Oscillator Needs Adjustment Send it back to be fixed. 42 Poor GPS Coverage Lost a SV required for a fix. 44 Receiver has Failed 45 Power Down and Re-init 46 Read Only Mem has Failed 47 RTCM Input has Failed DGPS input has stoped 48 No RTCM Input It can't find DGPS input. 49 Searching the Sky Looking for SVs. Lost some alminac data. 50 Steep Turn Ahead 51 Inside SUA 52 SUA Near & Ahead 53 SUA Ahead < 10 min 54 Near SUA < 2 nm This is the list of internal datums. These do not match the count from Garmin or the list that GarDown7 has. Are some of these repeats? 0 Adindan 1 Afgooye 2 AIN EL ABD '70 3 Anna 1 Ast '65 4 ARC 1950 5 ARC 1960 6 Ascnsn Isld '58 7 Astro B4 Sorol 8 Astro Bcn "E" 9 Astr Dos 71/4 10 Astro Stn '52 11 Astrln Geod '66 12 Astrln Geod '84 13 Austria 14 Bellevue (IGN) 15 Bermuda 1957 16 Bogota Observ 17 Campo Inchspe 18 Canton Ast '66 19 Cape 20 Cape Canavrl 21 Carthage 22 CH-1903 23 Chatham 1971 24 Chua Astro 25 Corrego Alegr 26 Djakarta 27 Dos 1968 28 Easter Isld 67 29 European 1950 30 European 1979 31 Finland Hayfrd 32 Gandajika Base 33 Geod Datm '49 34 Guam 1963 35 Gux 1 Astro 36 Hjorsey 1955 37 Hong Kong '63 38 Hu-Tzu-Shan 39 Indian Bngldsh 40 Indian Thailand 41 Indonesia 74 42 Ireland 1965 43 ISTS 073 Astro 44 Johnston Island 45 Kandawala 46 Kergueln Islnd 47 Kertau 1948 48 L.C. 5 Astro 49 Liberia 1964 50 Luzon Mindanao 51 Luzon Philippine 52 Mahe 1971 53 Marco Astro 54 Massawa 55 Merchich 56 Midway Ast '61 57 Minna 58 NAD27 Alaska 59 NAD27 Bahamas 60 NAD27 Canada 61 NAD27 Canal Zn 62 NAD27 Caribbn 63 NAD27 Central 64 NAD27 CONUS 65 NAD27 Cuba 66 NAD27 Grnland 67 NAD27 Mexico 68 NAD27 San Sal 69 NAD83 70 Nhrwn Masirah 71 Nhrwn Saudi A 72 Nhrwn United A 73 Naparima BWI 74 Obsrvtorio '66 75 Old Egyptian 76 Old Hawaiian 77 Oman 78 Ord Srvy GB 79 Pico De Las Nv 80 Potsdam 81 Ptcairn Ast '67 82 Prov S Am '56 83 Prov S Chln '63 84 Puerto Rico 85 Qatar National 86 Qornoq 87 Reunion 88 Rome 1940 89 RT 90 90 Santo (Dos) 91 Sao Braz 92 Sapper Hill '43 93 Schwarzeck 94 Sth Amrcn '69 95 South Asia 96 SE Base 97 SW Base 98 Timbalai 1948 99 Tokyo 100 Tristan Ast '68 101 Viti Levu 1916 102 Wake-Eniwetok 103 WGS 72 104 WGS 84 105 Zanderij 106 User