BCM88335 Data Sheet
WLAN GPIO Signals and Strapping Options
Multiplexed Bluetooth GPIO Signals
The Bluetooth GPIO pins (BT_GPIO_0 to BT_GPIO_7) are multiplexed pins and can be programmed to be used
as GPIOs or for other Bluetooth interface signals such as I2S. The specific function for a given BT_GPIO_X pin
is chosen by programming the Pad Function Control register for that specific pin. Table 19 shows the possible
options for each BT_GPIO_X pin. Note that each BT_GPIO_X pin's Pad Function Control register setting is
independent (BT_GPIO_1 can be set to pad function 7 at the same time that BT_GPIO_3 is set to pad
function 0). When the Pad Function Control register is set to 0, the BT_GPIOs do not have specific functions
assigned to them and behave as generic GPIOs. The A_GPIO_X pins described below are multiplexed behind
the BCM88335's PCM and I2S interface pins.
Table 19: GPIO Multiplexing Matrix
Pad Function Control Register Setting
Pin Name
0
1
2
3
4
5
6
7
15
BT_UART_CTS_ UART_CTS_N –
N
–
–
–
–
–
A_GPIO[1]
–
BT_UART_RTS_ UART_RTS_N –
N
–
–
–
–
–
A_GPIO[0]
–
BT_UART_RXD UART_RXD
–
–
–
–
–
–
–
–
–
–
–
–
GPIO[5]
GPIO[4]
–
BT_UART_TXD
BT_PCM_IN
UART_TXD
A_GPIO[3]
–
–
–
–
PCM_IN
PCM_IN
HCLK
I2S_SSDI/
MSDI
SF_MISO
BT_PCM_OUT
A_GPIO[2]
PCM_OUT PCM_OUT LINK_IND
–
I2S_MSDO –
I2S_MWS
I2S_SSDO SF_MOSI
BT_PCM_SYNC A_GPIO[1]
PCM_SYNC PCM_SYN HCLK
C
INT_LPO
–
I2S_SWS
I2S_SSCK
STATUS
SF_SPI_CS
N
BT_PCM_CLK
A_GPIO[0]
PCM_CLK
PCM_CLK
–
–
I2S_MSCK –
SF_SPI_CL
K
BT_I2S_DO
BT_I2S_DI
A_GPIO[5]
A_GPIO[6]
PCM_OUT
PCM_IN
–
–
–
I2S_SSDO I2S_MSDO –
–
HCLK
I2S_SSDI/
MSDI
–
–
TX_CON_FX –
BT_I2S_WS
BT_I2S_CLK
BT_GPIO_1
BT_GPIO_0
CLK_REQ
GPIO[7]
GPIO[6]
GPIO[1]
GPIO[0]
PCM_SYNC
–
–
–
–
–
LINK_IND
–
I2S_MWS
–
I2S_SWS
I2S_SSCK
CLASS1[2]
–
–
–
–
–
–
PCM_CLK
–
–
–
–
INT_LPO
I2S_MSCK –
–
–
–
–
–
–
–
–
–
–
clk_12p288
–
WL/
A_GPIO[7]
BT_CLK_REQ
Broadcom®
September 23, 2015 • 88335-DS100-R
Page 83
BROADCOM CONFIDENTIAL
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