Specifications

Power Interface
Rev 2.0 Apr.10 Proprietary and Confidential 21
State change: Normal mode to Low Power mode
This state change causes the module to suspend RF activity. It occurs when the
module’s supply voltage exceeds either the high (VOLT_HI_CRIT) or low
(VOLT_LO_CRIT) limits detailed in Ta bl e 2 -1 on page 20.
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) as appropriate.
State change: Low Power mode to Normal mode
This state change causes the module to resume RF activity. It occurs when the
module’s supply voltage returns from critical to normal limits as described in
Tabl e 2- 1 on page 20 (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) as appropriate.
State change: Power off/on
Note: The module is still
connected to the power
source in this state,
drawing minimal power.
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
W_Disable# signal low for:
•
 50 ms (MC8775/MC8775V)
•
 500 ms (MC5727/MC5727V/ MC5728V/MC8201/MC8700/MC8780/
MC8781/MC8790/MC8790V/MC8791V/MC8792V/MC8795V)
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 W_Disable# signal
floating (high impedance) as shown in 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.
3. The host has the option, at this point, of driving W_Disable# low (forcing the
module to power off) to prevent damage to the unit.