BCM43455 Preliminary Data Sheet
External Coexistence Interface
External Coexistence Interface
An external handshake interface is available to enable signaling between the device and an external co-located
wireless device, such as GPS or LTE to manage wireless medium sharing for optimum performance.
Figure 23 shows the WCI-2 LTE coexistence interface. See Table 13: “UART Timing Specifications,” on page 57
for UART baud rate.
Figure 23: Broadcom GCI or BT-SIG WCI-2 LTE Coexistence Interface
LTE\IC
SECI_OUT/BT_TXD/GPIO5
SECI_IN/BT_RXD/GPIO4
UART_IN
WLAN
BT
GCI
UART_OUT
BCM43455
NOTES:
SECI_OUT/BT_TXD and SECI_IN/BT_RXD on the BCM4345X are multiplexed on GPIO5 and GPIO4, respectively.
The 2-wire LTE coexistence interface is intended for future compatibility with the BT SIG2-wire interface that is being standardized for
Core 4.1.
ORing to generate ISM_RX_PRIORITY for ERCX_TXCONF or BT_RX_PRIORITY is achieved by setting the GPIO mask registers
appropriately.
Figure 24 and Table 15 on page 66 define an alternate 3-wire LTE coexistence interface.
Figure 24: 3-Wire LTE Coexistence Interface
LTE\IC
GPIO2
GPIO3
GPIO4
ERCX_WL_PRIO
ERCX_LTETX
ERCX_LTERX
WLAN
BT
ERCX
BCM43455
Table 15: 3-Wire External Coexistence Interface
GPIO Name Coexistence Signal
Type
Comment
GPIO_2
GPIO_3
GPIO_4
ERCX_WL_PRIO
ERCX_LTE_TX
ERCX_LTE_RX
Output
Input
Notify LTE of request to sleep
Notify WLAN RX of requirement to sleep
Notify WLAN TX to reduce TX power
Input
Broadcom®
November 5, 2015 • 43455-DS109-R
Page 66
BROADCOM CONFIDENTIAL
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