Integration Guide
Table Of Contents
- Preface
- Contents
- 1 System description
- 1.1 Overview
- 1.2 Architecture
- 1.3 Pin-out
- 1.4 Operating modes
- 1.5 Power management
- 1.6 System functions
- 1.7 RF connection
- 1.8 SIM interface
- 1.9 Serial Communication
- 1.10 Audio
- 1.11 ADC input (LEON-G100 only)
- 1.12 General Purpose Input/Output (GPIO)
- 1.13 M2M Setup Schematic Example
- 1.14 Approvals
- 2 Design-In
- 3 Handling and soldering
- 4 Product Testing
- Appendix
- A Extra Features
- B Glossary
- Related documents
- Revision history
- Contact
LEON-G100/G200 - System Integration Manual
GSM.G1-HW-09002-F3 Preliminary System description
Page 44 of 101
TxD signal behavior
The module data input line (TxD) is set by default to OFF state (high level) at UART initialization. The TxD line is
then held by the module in the OFF state if the line is not activated by the DTE: an active pull-up is enabled
inside the module on the TxD input.
CTS signal behavior
The module hardware flow control output (CTS line) is set to the ON state (low level) at UART initialization.
If the hardware flow control is enabled (for more details please refer to u-blox 2G GSM/GPRS AT Commands
Manual [2], AT&K, AT\Q, AT+IFC AT command) the CTS line indicates when the module is in active mode and
the UART interface is enabled: the module drives the CTS line to the ON state or to the OFF state when it is
either able or not able to accept data from the DTE (refer to chapter 1.9.1.3 for the complete description).
If the hardware flow control is not enabled, the CTS line is always held in the ON state after UART initialization.
When the power saving configuration is enabled and the hardware flow-control is not implemented in
the DTE/DCE connection, data sent by the DTE can be lost: the first character sent when the module is in
idle-mode won’t be a valid communication character (refer to chapter 1.9.1.3 for the complete
description).
During the MUX mode, the CTS line state is mapped to FCon / FCoff MUX command for flow control
issues outside the power saving configuration while the physical CTS line is still used as a power state
indicator. For more details please refer to Mux Implementation Application Note [14].
RTS signal behavior
The hardware flow control input (RTS line) is set by default to the OFF state (high level) at UART initialization.
The RTS line is then held by the module in the OFF state if the line is not activated by the DTE: an active pull-up
is enabled inside the module on the RTS input.
If the HW flow control is enabled (for more details please refer to u-blox GSM/GPRS AT Commands Manual [2]
AT&K, AT\Q, AT+IFC command description) the RTS line is monitored by the module to detect permission from
the DTE to send data to the DTE itself. If the RTS line is set to OFF state, any on-going data transmission from
the module is immediately interrupted or any subsequent transmission forbidden until the RTS line changes to
ON state.
The DTE must be able to still accept a certain number of characters after the RTS line has been set to
OFF state: the module guarantees the transmission interruption within 2 characters from RTS state
change.
If AT+UPSV=2 is set and HW flow control is disabled, the RTS line is monitored by the module to manage the
power saving configuration:
When an OFF-to-ON transition occurs on the RTS input line, the module switches from idle-mode to
active-mode after 20 ms and the module doesn’t enter idle-mode until the RTS input line is held in the ON
state
If RTS is set to OFF state by the DTE, the module automatically enters idle-mode whenever possible as in the
AT+UPSV=1 configuration (cyclic idle/active mode)
For more details please refer to chapter 1.9.1.3 and u-blox 2G GSM/GPRS AT Commands Manual [2], AT+UPSV
command.
DSR signal behavior
If AT&S0 is set, the DSR module output line is set by default to ON state (low level) at UART initialization and is
then always held in the ON state.