User Manual

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USERS MANUAL
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4/198 17-LXE 108 566 Uen PA6
3.1.1 MODULE_PWR_EN_B
This signal, located on pin 12 in the system connector, enables the main 5V supply in
the phone module so that it powers on. This is an open collector input to the phone
module. Its reference voltage is the main 5V supply.
3.1.2 VREF
This signal, located on pin 2 in the system connector, provides the application with its
logic supply voltage. The application can current-amplify this signal and use it to supply
its interface circuits.
3.1.3 HW_SD
This signal, located on pin 15 in the system connector, provides the ability of performing
a hardware shutdown of the module. It is a bi-directional signal that is pulled up inside
the phone module.
Shut down sequence:
1 To request a shutdown of the phone module, the application should provide an
active low pulse of 100 ± 25 ms on the HW_SD pin through an open collector
output.
2 This pulse is detected by the module, which confirms the request by enabling its
HW_SD output, setting it active low.
3 The application waits for the HW_SD pin to become inactive high.
4 The module has performed its power down sequence and disables its output
resulting in HW_SD becoming inactive high.
5 The application shuts down, disabling MODULE_PWR_EN_B.
Shutdown
Indicate
Shutdown
Request
Shutdown
Confirm
Shutdown
Detect
VREF
15, HW_SD
Application Phone Module