Product Info
Table Of Contents
- About the Document
- Contents
- Table Index
- Figure Index
- 1 Introduction
- 2 Product Concept
- 3 Application Interfaces
- 3.1. General Description
- 3.2. Pin Assignment
- 3.3. Pin Description
- 3.4. Operating Modes
- 3.5. Power Saving
- 3.6. Power Supply
- 3.7. Power-on/off Scenarios
- 3.8. Reset the Module
- 3.9. (U)SIM Interfaces
- 3.10. USB Interface
- 3.11. UART Interfaces
- 3.12. PCM and I2C Interfaces
- 3.13. SPI Interface
- 3.14. Network Status Indication
- 3.15. STATUS
- 3.16. ADC Interface
- 3.17. Behaviors of RI
- 3.18. USB_BOOT Interface
- 4 GNSS Receiver
- 5 Antenna Interfaces
- 6 Electrical, Reliability and Radio Characteristics
- 7 Mechanical Dimensions
- 8 Storage, Manufacturing and Packaging
- 9 Appendix A References
- 10 Appendix B GPRS Coding Schemes
- 11 Appendix C GPRS Multi-slot Classes
- 12 Appendix D EDGE Modulation and Coding Schemes
LTE Standard Module Series
EG91 Hardware Design
EG91_Hardware_Design 44 / 93
MCU/ARM
TXD
RXD
VDD_EXT
10K
VCC_MCU
4.7K
10K
VDD_EXT
TXD
RXD
RTS
CTS
DTR
RI
RTS
CTS
GND
GPIO DCD
Module
GPIO
EINT
VDD_EXT
4.7K
GND
1nF
1nF
Figure 21: Reference Circuit with Transistor Circuit
Transistor circuit solution is not suitable for applications with high baud rates exceeding 460Kbps.
3.12. PCM and I2C Interfaces
EG91 provides one Pulse Code Modulation (PCM) digital interface for audio design, which supports the
following modes and one I2C interface:
Primary mode (short frame synchronization, works as both master and slave)
Auxiliary mode (long frame synchronization, works as master only)
In primary mode, the data is sampled on the falling edge of the PCM_CLK and transmitted on the rising
edge. The PCM_SYNC falling edge represents the MSB. In this mode, the PCM interface supports 256KHz,
512KHz, 1024KHz or 2048KHz PCM_CLK at 8KHz PCM_SYNC, and also supports 4096KHz PCM_CLK
at 16KHz PCM_SYNC.
In auxiliary mode, the data is also sampled on the falling edge of the PCM_CLK and transmitted on the
rising edge. The PCM_SYNC rising edge represents the MSB. In this mode, the PCM interface operates
with a 256KHz, 512KHz, 1024KHz or 2048KHz PCM_CLK and an 8KHz, 50% duty cycle PCM_SYNC.
EG91 supports 16-bit linear data format. The following figures show the primary mode’s timing relationship
with 8KHz PCM_SYNC and 2048KHz PCM_CLK, as well as the auxiliary mode’s timing relationship with
8KHz PCM_SYNC and 256KHz PCM_CLK.
NOTE