Specifications

Power Interface
Rev 2.0 Apr.10 Proprietary and Confidential 23
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. As well, the MC57xx issues the CnS notification Modem
Too Hot [0x4500] if it has to drop a call when shifting to low power mode.
State change: Low Power mode to Normal mode
This state change causes the module to resume RF activity. It occurs when the
module temperature returns from critical to normal limits as described in Ta bl e 2 - 2
on page 22 (TEMP_HI_NORM and TEMP_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
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 2-3 on page 22 shows the transition from ‘Low Temperature Critical’ or
‘High Temperature Critical’ to ‘Power off’.
1. The module enters low power mode because it detects that the operating
temperature is critically low (TEMP_LO_CRIT) or critically high
(TEMP_HI_CRIT).
2. The module sends a CnS notification (Return Radio Temperature—0x0008)
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.
Note: (MC57xx only) If the ambient temperature of the module exceeds 60°C, the RF level
is automatically lowered for max power transmission.