BCM88335 Data Sheet
Bluetooth Power Management Unit
Figure 6: Startup Signaling Sequence
LPO
Host IOs
unconfigured
VDDIO
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
BT_UART_RTS_N
BTH device drives this
low indicating
T4
transport is ready.
CLK_REQ_OUT
Notes :
T5
Driven
Pulled
ꢀꢁ 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®
September 23, 2015 • 88335-DS100-R
Page 38
BROADCOM CONFIDENTIAL
CYPRESS [ CYPRESS ]
