Have Geek Brain

Built-in mobile phone code

What do most mobile phones use to run equipment? FROM?

I'm just talking about "shared mobile", not smartphone / android.

+1


a source to share


7 replies


I work for a wireless semiconductor chip supplier and we work on a variety of phone platforms from ULC (ultra low) to smartphones.



In our reference phone, all code (including protocol stack, kernel, middleware, application and MMI) is written exclusively in C. AFAIK, even first level clients use C language for their structure, at least for ULC and Mid category phones, so how the size of memory matters a lot.

+2


a source


Phones running various Symbian OSs are likely to have all the functionality of a C ++ OS, since it is the native Symbian language.



+1


a source


Speaking of cell phones, it usually has two processor components.

  • The "main" processor that spans the user interface.
  • The "baseband" processor that powers the cellular modem. It handles low-level radio interface, switching towers, etc.

The code for # 1 tends to be higher (C, C ++, Java, etc.). The language used really depends on the OS it runs on (Windows Mobile, Symbian, Linux, homemade, etc.). Of course, there is almost always SOME low-level build for the bootloader.

The code for # 2 is pretty low level. Baseband processors are generally nothing more than microcontrollers. Basically assembly language and C. It is very unlikely to find anything higher. (I've seen a few modem cells with a built-in Python interpreter though.)

Typically the baseband processor runs some sort of minimal RTOS, and in some cases OS-less. They use RTOS very often called Nucleus from Mentor Graphics.

On some low-cost cell phones, # 1 and # 2 are bundled together to cut costs (only one processor and OS per system).

+1


a source


Hardware such as setup and interrupt handling registers for starting the radio is done in C.

The two problems with C ++ are in my opinion that

  • It is more difficult to design effective programs in it. The processor can be as small as a few hundred MHz.
  • Compilers for more exotic processors barely run in C, so running them in C ++ would be a miracle.
0


a source


Android phones will use mostly C under the java machine and Java in the upper layers.

But if you look at most phones, they are like the rest of the embedded market, that's a lot of c , and in some project, some C ++.

And the smaller they are, the more c you will find.

/ Johan

0


a source


Most cell phones have different software levels, and in many ways we can divide this into three parts.

1.Application Layer: something like BREW, C ++ or Android

2. Middle level: Consists of real-time OS code: C code [mostly as I've seen]

3.Lower-Layer: Device Drivers: Written in C.

note: most common mobile phones will probably use C ++ as the application layer, Brew is mainly used by CDMA phones for the application layer

0


a source


Nokia bought Trolltech, the makers of Qt, a cross-platform application and user interface for desktop and mobile applications. Presumably this includes cell phones. Qt is written in C ++. http://www.qtsoftware.com/developer/getting-started

-1


a source






More articles:


All Articles