Cartesio chipset used in Garmin Nuvi 255w GPS

I've been wondering what kind of GPS chipset is inside my Garmin Nuvi 255w GPS. Some say it is the famous SiRFstarIII, some say it is the Taiwanese MTK chipset, but I find out that it is actually the STMicro Cartesio.

In fact, all the current Garmin Nuvi 2x5 series of GPS are using this Cartesio automotive-grade infotainment application processor with embeded GPS receiver. It features the System-on-Chip (SoC) technology which combines the host CPU and a high-performance 32-channel GPS correlator, and also a large set of peripherals and interfaces.

Here are some of the technical information about the STMicro Cartesio (code name STA2062):

• High performance ARM926 333-MHz CPU
• High performance 32-channel GPS correlator
• Bus/DDR frequency is 166 MHz
  
• 32 KB embedded ROM for boot
• 2 banks of 64 KB embedded SRAM
• 0.5 KB embedded SRAM for back-up
• 4 GB total linear address space
  
• Operating temperature range from -40 to 85 °C

Click here for more information on the STMicro Cartesio.

My GPS usage experience shows that this STMicro Cartesio is performing pretty good.

Switch the Garmin Nuvi GPS to Simulator Mode and vice-versa

The Garmin Nuvi GPS will automatically prompt you an option to switch to Simulator Mode when it is not able to contact with the satellites. Simulator Mode allows you to use the functions of the GPS, such as planning for a route to destination, even when you are indoor and cannot get satellites signal. Simulator Mode is very useful when you want to demo the GPS functions to others.

You can manually set the GPS into Simulator Mode, even when the GPS is able to get ssatellites signal, by going to Tools > Settings > System > GPS Mode and select "GPS Off". The GPS signal strength indicator on the top-left corner of the screen will have a red cross when you are in Simulator Mode.



From the Simulator Mode, you can switch your GPS back to "Normal" mode and start acquiring satellites signal by going to the same setting place.

View the complete route to destination in Garmin Nuvi GPS

After you have set your destination in Garmin Nuvi GPS and before you tap on the "Go" button, you can actually view the complete route that your GPS has calculated by tapping on the "Route Info" area.

You might need some passion to wait for the calculation to complete, and it might take some seconds before the "Route Info" area slide out and appear on the screen.

A map will appear after you tap on the "Route Info" area. The route to your destination will be shown as a magenta line in the map.

You can tap on the [+] button to enlarge the map, drag the map will your finger to scroll the display area.

If you are already in the Map Screen showing your route to destination, you can also reach the above map showing the complete route by first tapping on the green bar which display the current road name on top of the screen, then tap on the "Show Map" button below the next screen.

If you don't like this calculated route, try to adjust your Avoidances setting in Tools > Settings > Navigation > Avoidances. Then try again.

If you still don't like the calculated route, you can also inform the GPS to make a detour.