Sierra Wireless MC5725 Hardware Integration Manual page 21

Note: The module is still
connected to the power source
in this state, drawing minimal
power.
Rev 1.9.1 Feb.09
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.
State change: Normal mode to Low Power mode
This state change causes the module to switch to low power
mode, suspending RF activity. It occurs when the module's
supply voltage exceeds the limits described in Table 2‐1
(VOLT_HI_CRIT and VOLT_LO_CRIT).
When this state change occurs, the CnS notification
CNS_RADIO_POWER is issued, if enabled. For a detailed
description of this notification, see CDMA CnS Reference
(Document 2130754) or MC87XX Modem CnS Reference
(Document 2130602).
State change: Low Power mode to Normal mode
This state change causes the module to switch to normal mode,
resuming RF activity. It occurs when the module's supply
voltage returns from critical to normal limits as described in
Table 2‐1 (VOLT_HI_NORM and VOLT_LO_NORM).
When this state change occurs, the CnS notification
CNS_RADIO_POWER is issued, if enabled. For a detailed
description of this notification, see CDMA CnS Reference
(Document 2130754) or MC87XX Modem CnS Reference
(Document 2130602).
State change: Power off / on
The module begins a shutdown sequence and powers off if it
has been in a powered‐on state for more than 10.5 seconds and
the host device drives the
≥
• 50 ms (MC8775 / MC8775V)
≥
500 ms (MC5725 / MC5725V / MC5727 / MC5727V /
•
MC5728 / MC5728V / MC8780 / MC8781 / MC8785V /
MC8790 / MC8790V / MC8791V / MC8792V)
Note: The module ignores changes in the W_Disable# line for the first
10.5 seconds after it enters a powered-on state.
The module powers on when the host device leaves the
# signal floating (high impedance) as shown in
W_Disable
Figure 2‐1 on page 17.
Figure 2‐2 on page 20 shows the transition from 'Low Supply
Voltage Critical' or 'High Supply Voltage Critical' to 'Power
off':
1. The module enters low power mode because it detects that
the supply voltage level is critically low (VOLT_LO_CRIT)
or critically high (VOLT_HI_CRIT).
2. The module sends a CnS notification (Return Radio
Voltage—0x0009) to the host indicating that it is now in
low power mode.
Proprietary and Confidential
Power Interface
# signal low for:
W_Disable
21