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Note d’étude / Technical document : URD1 – 5625.1 – 006 / 69796 Edition 03

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3.14 Hardware Power management and multiplexing interfaces

In case hardware power management and multiplexing are used, it is necessary to isolate host and module

MO300 in order to not generate current re-injection when MO300 is switched-off.

Typical schematics (only useful signals are represented):

Figure 26

Hardware interface between MO300 and host

In a general case, solution 1 ( cheaper) is enough to protect the module MO300.

3.15 Resetting the module

The MO300 module supports 2 kinds of reset:

• External software reset activated by the AT command as defined in the document referenced [2]

• External level 1 priority Hardware reset by pulling down the PWON* signal more than 8.2 seconds, on the

next rise of PWON* the module is trigged. The reset is done 8.2 seconds later. This hardware reset, resets

all the registers as well as the real time clock register, it is unconditional and have the highest priority. The

module is in off mode after this hardware reset and need a new starting sequence to start again. At least

16.4 seconds are necessary to perform the hardware reset.

3.16 Starting the module

There are two ways to start the MO300 module.

3.16.1 Use of PWON*

First power up VBAT, which must be in the range 3.3V – 4.5V, and able to provide at least 2A during the TX

bursts (refer to the module specification for more details).

To start the module, a low level pulse must be sent on PWON* during more than 31.25ms (at 25°C). This

duration increases as the temperature decreases (up to ~ 1 second at –30°C).

After ~3 seconds CTS is active and so MOD_ON_STATE when it is ready to receive AT commands.

To be sure that the pulse duration is enough to start the module, independently from the temperature,

MOD_ON_STATE can be used as feedback to stop the pulse:

DTR,RTS, RXD

CTS, DSR, DCD, RI, TXD

DTE_UART*_STATE,

MOD_RESET_STATE,

MOD_UART_STATE,

MOD_FLOW_STATE,

MOD_ON_STATE

Tri-state command

MO300

HOST

(

)

VREXTH

Tri-state

Buffers

100K

Solution 1

Solution 2