Q2686 Wavecom, Q2686 Datasheet - Page 54

• Manufacturer Part Number: Q2686
• Description: Wireless CPU
• Manufacturer: Wavecom

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Proceeding thus – by software detection - will always prevent the application
from de-asserting the ON/~OFF signal too early.
If WIND indicators are disabled or AT commands unavailable or not used, it is
still possible to de-assert ON/~OFF after a delay long enough (T
ensure that the firmware has already completed its power-up initialization.
The table below gives the minimum values of T
The above figure take the worst cases into account: power-loss recovery
operations, slow flash memory operations in high temperature conditions, and
so on. But, they are safe because they are large enough to ensure that
ON/~OFF is not de-asserted too early.
Additional notes:
This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged without
prior written agreement.
WM_PRJ_Q2686_PTS_001-007
1.
2.
3.
4.
5.
Typical power-up initialization time figures for best cases conditions
(no power-loss recovery, fast and new flash memory…) approximate
3.5 seconds in every firmware version. But releasing ON/~OFF after
this delay does not guarantee that the application will actually start-up
if for example the power plug has been pulled off during a flash
memory operation, like a phone book entry update or an AT&W
command…
The ON/~OFF signal can be left at a high level until switch OFF. But
this is not recommended as it will prevent the AT+CPOF command
from performing a clean power-off. (see also Note in section 3.14.1.2
on Power-OFF for an alternate usage)
When using a battery as power source, it is not recommended to let
this signal high:
If the battery voltage is too low and the ON/~OFF signal at low level,
an internal mechanism switches OFF the Wireless CPU
automatic process prevents the battery to be over discharged and
optimize its life span.
During the power-ON sequence, an internal reset is automatically
performed by the Wireless CPU
should be avoided during this phase.
Connecting a charger on the Wireless CPU
than setting the ON/~OFF signal. In particular the Wireless CPU
not POWER-OFF after the AT+CPOF command, unless the Charger is
disconnected.
Open AT
6.60 & above
confidential ©
®
Firmware
T
on/off-hold
Safe evaluations of the firmware
minimum values
®
for 40 ms (typical). Any external reset
power-up time
T
on/off-hold
on/off-hold
8 s
®
as exactly the same effect
Q2686 Wireless CPU
:
on/off-hold
Interfaces
®
. This
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March 6, 2007
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will
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