BCM4339 Preliminary Data Sheet
Bluetooth Power Management Unit
Table 4: Power Control Pin Description (Cont.)
Signal
Mapped to Pin
Type Description
O The BCM4339 asserts CLK_REQ when either the Bluetooth
CLK_REQ
BT_CLK_REQ_OUT
WL_CLK_REQ_OUT
or WLAN block wants the host to turn on the reference clock.
The CLK_REQ polarity is active-high. Add an external 100
kΩ pull-down resistor to ensure the signal is deasserted
when the BCM4339 powers up or resets when VDDIO is
present.
Note: Pad function Control Register is set to 0 for these pins. See “DC Characteristics” on page 122 for more
details.
Figure 6: Startup Signaling Sequence
LPO
Host IOs
VDDIO
unconfigured
Host IOs configured
T1
HostResetX
BT_GPIO_0
(BT_DEV_WAKE)
BT_REG_ON
T2
BTH IOs
unconfigured
BTH IOs configured
BT_GPIO_1
(BT_HOST_WAKE)
T3
Host drives
this low.
BT_UART_CTS_N
BTH device drives this
low indicating
BT_UART_RTS_N
CLK_REQ_OUT
T4
transport is ready.
T5
Driven
Pulled
Notes :
ꢀꢁ T1 is the time for the host to settle its IOs after a reset.
ꢀꢁ T2 is the time for the host to drive BT_REG_ON high after the host IOs are configured.
ꢀꢁ T3 is the time for the BTH device to settle its IOs after a reset and the reference clock settling time has elapsed.
ꢀꢁ T4 is the time for the BTH device to drive BT_UART_RTS_N low after the host drives BT_UART_CTS_N low. This assumes
the BTH device has completed initialization.
ꢀꢁ T5 is the time for the BTH device to drive CLK_REQ_OUT high after BT_REG_ON goes high. The CLK_REQ_OUT pin is used
in designs that have an external reference clock source from the host. It is irrelevant on clock-based designs where the
BTH device generates its own reference clock from an external crystal connected to its oscillator circuit.
ꢀꢁ The timing diagram assumes that VBAT is present.
Broadcom®
November 17, 2014 • 4339-DS106-R
Page 42
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