Sim800 hardware design v1.05
Table Of Contents
- Version History
- 1. Introduction
- 2. SIM800 Overview
- 3. Package Information
- 4. Application Interface
- 4.1. Power Supply
- 4.2. Power on/down SIM800
- 4.3. Power Saving Mode
- 4.4. RTC Backup
- 4.5. Serial Port and USB Interface
- 4.6. RI Behaviors
- 4.7. Audio Interfaces
- 4.8. Bluetooth
- 4.9. SIM Card Interface
- 4.10. PCM Interface
- 4.11. Keypad Interface
- 4.12. I2C BUS
- 4.13. General Purpose Input/Output (GPIO)
- 4.14. ADC
- 4.15. PWM
- 4.16. Network Status Indication
- 4.17. Operating Status Indication
- 4.18. KPLED
- 4.19. RF Synchronization Signal
- 4.20. Antenna Interface
- 5. PCB Layout
- 6. Electrical, Reliability and Radio Characteristics
- 6.1 Absolute Maximum Ratings
- 6.2 Recommended Operating Conditions
- 6.3 Digital Interface Characteristics
- 6.4 SIM Card Interface Characteristics
- 6.5 SIM_VDD Characteristics
- 6.6 VDD_EXT Characteristics
- 6.7 VRTC Characteristics
- 6.8 Current Consumption (VBAT=4V)
- 6.9 Electro-Static Discharge
- 6.10 Radio Characteristics
- 6.11 Module RF Receive Sensitivity
- 6.12 Module Operating Frequencies
- 7. Manufacturing
- 8. Appendix
Smart Machine Smart Decision
4.10.4. SD Card Interface
Module
DAT2
DAT3
CMD
VDD
CLK
VSS
DAT0
DAT1
MC3DA2
MC3DA3
MC3CM0
VDD_EXT
MC3CK
VSS
MC3DA0
MC3DA1
SD
card
Figure 38: SD reference circuit
If the VDD of SD card is 2.8V, user can use VDD_EXT power the SD card directly. If the VDD is 3.3V,
customer should design the power circuit external.
4.11. Keypad Interface
SIM800 consists of 5 keypad column outputs and 5 keypad row inputs, and it can support two kinds of
connections, the traditional 5*5 keypad matrix and the extended 5*5*2 keypad matrix.
Figure 39: Traditional keypad reference circuit
Note: According to the traditional 5*5 keypad matrix, when there are unused COLs or ROWs, user can execute
AT command to define unused COLs and ROWs as GPIO, for details please see the document [1].
SIM800_Hardware Design_V1.05 44 2014-03-25