Modem Startup Process in the mobile phone Startup Process (IV)-energy-saving mode & Security Code Initialization

This section describes the subsequent steps of the mobile phone modem startup process: energy-saving mode and security code initialization.

 

Energy-saving mode:

To reduce power consumption, mobile phone modem generally provides energy-saving mode for users to choose from. Generally, modem supports doze mode or cyclic sleep mode ).

When the current modem of the mobile phone is idle, it will enter the energy-saving mode to avoid excessive power consumption. The standard at command is at + cfun.

In the mobile phone startup process, you can select different command sets to set the power-saving mode of the modem at the current Boot.

The implementation of the dummy mode is as follows:

When a modem enters the false standby mode, the CPU frequency is reduced. When a foreign request arrives at the modem, the request is cached in the peripheral storage area of the modem. After the cache is completed, the processor is adjusted to the normal mode to process requests cached in the peripheral storage area and enters the counterfeit mode again after processing.

The implementation of the periodical sleep mode is as follows:

After the modem is started, it wakes up every few "multiple frames" (about 1/8 seconds) when it is idle. The system can instruct the modem to wake up at a certain time to check for external requests. This sacrifices the time required to detect the request. In energy-saving mode, the processor will turn off the receiver and bring itself into the low-power sleep mode. An Internal timer restarts the processor after appropriate sleep time.

The process of waking up is to enable the DC voltage of the RF circuit after the processor wakes up. First, it needs to turn on and adjust the synthesizer to make it have the opportunity to stabilize, then it needs to open each analog amplifier section of the receiver and instruct them to execute their respective calibration routines. The antenna switch must be switched to "receive" and the RF front-end must be enabled. The DSP starts and starts to convert the received burst data. Once the data is received, the RF and analog parts of the receiver are closed, and the DSP decodes the received data, and the processor determines how to process the data. Unless the processor needs to take actions based on the data, it will put itself into sleep until the next wake-up.

The text at both ends references the link content:

Phone RF "sleep mode" can extend cell phone battery use time http://www.china001.com/show_hdr.php? Xname = ppddmv0 & dname = n29a061 & xpos = 38

 

Security code initialization:

Mobile phone generally involved in the password mainly include: SIM-PIN code, SIM-PUK code, SIM-PIN2 code, SIM-PUK2 code

The security code initialization involved in the modem initialization process mainly queries the status of the current SIM card (whether the SIM card pin code is locked or whether the PUK code is locked ...)

At command: At + cpin? Obtains the current mobile phone security code status.

At ^ spic get the current security code count (enter several more times to be locked)

At + cpin at + cpin2 enter the security code to unlock