User's Manual

9/29/2004 OV4F2
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User Manual BCM2035
04/23/03
Broadcom Corporation
Document 2035-UM100-R Bluetooth Baseband Core Page 11
Host Controller Power Management
When running in USB mode, the BCM2035 supports the USB version 1.1 specification, suspend/resume
signaling as well as remote wake-up signaling for power control.
When running in UART mode, the BCM2035 may be configured such that dedicated signals are used for power
management hand-shaking between the BCM2035 and the host. The basic power saving functions supported
by those hand-shaking signals include the standard Bluetooth defined power savings modes as well as
standby modes of operation.
An alternative to using the BT_WAKE and HOST_WAKE signaling uses the CTS and RTS as a combination
of UART hardware handshake signals during normal operation and as BT_WAKE and HOST_WAKE when the
device has been placed into a power savings mode, as described in
Table 1.
ADAPTIVE FREQUENCY HOPPING (AFH)
The BCM2035 gathers link quality statistics on a channel-by-channel basis to facilitate channel assessment
and channel map selection. The BCM2035 also integrates a programmable hardware acceleration engine and
frequency hop mapping tables to enable future support of AFH.
Table 1: Power Savings Mode Descriptions
Pin Direction Description
BT_WAKE Host Output
BT Input
Bluetooth Device wake-up: Signals from the host to the Bluetooth
device that the host requires attention.
Asserted = Wake up or remain awake (depending on context)
De-asserted = Bluetooth may sleep when sleep criteria are met.
This signal can be configured to be ASSERTED HIGH or ASSERTED
LOW via vendor specific command (HCI_Write_Sleep_Mode) or via
configuration data.
HOST_WAKE BT Output
Host Input
Host Wake-up: Signals from the Bluetooth device to the host that the
Bluetooth device requires attention.
Asserted = Wake up or remain awake (depending on context)
De-asserted = Host may sleep when sleep criteria are met.
This signal can be configured to be ASSERTED HIGH or ASSERTED
LOW via vendor specific command (HCI_Write_Sleep_Mode) or via
configuration data.
XTAL_PD BT Output Crystal Power-Down signal is ASSERTED by the
BCM2035 to indicate
that the system clock can be shut-down (this feature no longer requires
the device be in External LPO mode).
Crystal Power-Down mode:
Asserted = external frequency reference may be powered down
De-asserted = external frequency reference required
Crystal power down mode is set through the mode strap pins (TM[3:0]).
The Crystal Power-Down signal can be configured via the TM[3:0] bits
to be ASSERTED HIGH or ASSERTED LOW.