Installation Instructions
Table Of Contents
- Contents
- List of Table
- List of Figures
- 1 About this document
- 2 Product Overview
- 3 Mechanical Dimensions
- 4 Interface description
- 4.1 Pin Definition
- 4.2 Operating conditions
- 4.3 Digital logic characteristics
- 4.4 Power interface
- 4.5 USIM card interface
- 4.6 PCM interface
- 4.7 USB2.0 interface
- 4.8 UART interface
- 4.9 SPI interface
- 4.10 I2C interface
- 4.11 Network light
- 4.12 System Status Indication
- 4.13 Flight Mode
- 4.14 Forced USB download interface
- 4.15 SD card interface
- 4.16 SDIO_WIFI/EMMC interface
- 4.17 PCIe interface
- 4.18 RMII/RGMII interface
- 4.19 AUDIO interface
- 4.20 ADC
- 4.21 GPIOs
- 4.22 Power on/off and reset interface
- 4.23 Antenna interface
- 5 Product characteristics
- 6 Design Guideline
- 7 Storage, Production and Package
- 8 Safety Information
- 空白页面
- 空白页面
L508 Hardware Design
Copyright© Shanghai Mobiletek Communication Ltd 73
Figure 39 Power on sequence diagram
Note: the STATUS Pin is an indication of the module's running Status, and a high signal indicates that
the module is finished booting and initializing the process, otherwise the PIN is low
4.22.3 Power-off sequence
Modules have the following shutdown methods:
Shut down using the PWRKEY Pin
Shutdown using the "AT CPOF" command
Note: 1. For a detailed description of "AT + CPOF" , refer to documentation [1] .
2. Overvoltage (high or low) may also cause the module to shut down automatically.
3. Exceeding the limit temperature of the module may also cause the module to shut down
automatically.
Table 39 Power-off sequencing
Symbols Pin Name Min Typ Max Unit
TOFF Power off low level pulse width 16 -- -- s
TSTATUS
Shutdown time (judged by the
Status Pin)
25 26 -- s
TUART
BOOT time (according to UART
judgement)
14 15 -- s
Users can power off by pulling down the PWRKEY signal. The shutdown sequence is shown in the
following figure: