User's Manual
Table Of Contents
- Contents
- Table Index
- Figure Index
- 0. Revision history
- 1. Introduction
- 2. Product concept
- 3. Application interface
- 3.1. Pin
- 3.2. Operating modes
- 3.3. Power supply
- 3.4. Power on and down scenarios
- 3.5. Charging interface
- 3.6. Power saving
- 3.7. Summary of state transitions
- 3.8. RTC backup
- 3.9. Serial interfaces
- 3.10. Audio interfaces
- 3.11. SIM card interface
- 3.12. SD card interface
- 3.13. PCM interface
- 3.14. ADC
- 3.15. Behaviors of the RI
- 3.16. Network status indication
- 3.17. Operating status indication
- 4. Antenna interface
- 5. Electrical, reliability and radio characteristics
- 6. Mechanical dimensions
- 7. Storage and manufacturing
- Appendix A: GPRS coding schemes
- Appendix B: GPRS multi-slot classes
M80 Hardware Design
M80_HD_V1.2 - 59 -
Note: Please do not use “AT+QSIMDET=1,1” which causes to initialize SIM card when Figure
33 circuit is adopted.
If customer doesn’t need the SIM card detection function, keep SIM_PRESENCE open. The
reference circuit using a 6-pin SIM card socket is illustrated as the following figure.
Module
SIM_VDD
SIM_RST
SIM_CLK
SIM_DATA
22R
22R
22R
VCC
RST
CLK IO
VPP
GND
100nF
SIM_CARD
GND
GND
ESDA6V8V6
GND
Figure 34: Reference circuit of the 6 pins SIM card
In order to enhance the reliability and availability of the SIM card in the customer’s
application. Please follow the below criterion in the SIM circuit design
Keep layout of SIM card as close as possible to the module. Assure the possibility of the
length of the trace is less than 20cm.
Keep SIM card signal away from RF and VBAT alignment.
Assure the ground between module and SIM cassette short and wide. Keep the width of
ground no less than 0.5mm to maintain the same electric potential. The decouple capacitor of
SIM_VDD is less than 1uF and must be near to SIM cassette.
To avoid cross talk between SIM1_DATA and SIM1_CLK. Keep them away with each other
and shield them with surrounded ground
In order to offer good ESD protection, it is recommended to add TVS such as WILL
(http://www.willsemi.com) ESDA6V8AV6. The 22Ω resistors should be added in series
between the module and the SIM card so as to suppress the EMI spurious transmission and
enhance the ESD protection. Please to be noted that the SIM peripheral circuit should be
close to the SIM card socket.
3.11.2. 6 Pin SIM cassette
For 6-pin SIM card holder, it is recommended to use Amphenol C707 10M006 512 2. Please visit
http://www.amphenol.com for more information.