hardware design v1 00 2
Table Of Contents
- Contents
- Version History
- 1 Introduction
- 2 SIM900R Overview
- 3 Package Information
- 4 Application Interface
- 4.1 Power Supply
- 4.2 Power on/down Scenarios
- 4.3 Power Saving Mode
- 4.4 RTC Backup
- 4.5 Serial Interfaces
- 4.6 Audio Interfaces
- 4.7 SIM Card Interface
- 4.8 LCD Display/SPI Interface
- 4.9 Keypad Interface
- 4.10 ADC
- 4.11 RI Behaviours
- 4.12 Network Status Indication
- 4.13 General Purpose Input/Output (GPIO)
- 4.14 External Reset
- 4.15 PWM
- 4.16 I2C Bus
- 4.17 Antenna Interface
- 5 Electrical, Reliability and Radio Characteristics
- 5.1 Absolute Maximum Ratings
- 5.2 Recommended Operating Conditions
- 5.3 Digital Interface Characteristics
- 5.4 SIM Card Interface Characteristics
- 5.5 VDD_EXT Characteristics
- 5.6 SIM_VDD Characteristics
- 5.7 VRTC Characteristics
- 5.8 Current Consumption (VBAT = 3.8V)
- 5.9 Electro-Static Discharge
- 5.10 Radio Characteristics
- 6 Manufacturing
- Appendix
Smart Machine Smart Decision
Coin-type rechargeable battery is recommended, such as XH414H-IV01E form Seiko can be used.
Typical charge-discharge curves for this battery are shown in the following figure.
Figure 17: Seiko XH414H-IV01E Charge-Discharge Characteristic
4.5 Serial Interfaces
SIM900R provides two unbalanced asynchronous serial ports. One is the serial port and the other is the debug port.
The module is designed as a DCE (Data Communication Equipment). The following figure shows the connection
between module and client (DTE).
TXD
RXD
RTS
CTS
DTR
DCD
RI
TXD
RXD
RTS
CTS
DTR
DCD
RING
MODULE (DCE)
CUSTOMER (DTE)
Serial port1
Serial port
Debug port
Serial port2
DBG_RX
DBG_TX
TXD
RXD
Figure 18: Connection of the serial interfaces
If only RXD and TXD are used in user’s application, other serial pins should be kept open. Please refer to
following figure.
SIM900R_Hardware Design_V1.00 23 2012-07-20