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GPIO MUX

30       

NS9750B-A1 Datasheet 03/2006

AB3 gpio[46] U 4 I/O 00 Ser port D RTS

01 1284 nAutoFd (host-driven)

02 LCD data bit 22

03 GPIO 46

AA4 gpio[47] U 4 I/O 00 Ser port D CTS

01 1284 nInit (host-driven)

02 LCD data bit 23

03 GPIO 47

AC2 gpio[48] U 2 I/O 00 Timer 14

01 1284 SelectIn (host-driven)

02 DMA ch 2 req

03 GPIO 48

AD1 gpio[49]

U 2 I/O 00 Timer 15

01 1284 peripheral logic high (peripheral-driven)

02 DMA ch 2 done

03 GPIO 49

1 This pin is used for bootstrap initialization (see Table 1, “Configuration pins— Bootstrap initialization,”

on page 5). Note that the GPIO pins used as bootstrap pins have a defined powerup state that is

required for the appropriate NS9750B-A1 configuration. If these GPIO pins are also used to control

external devices (for example, power switch enable), the powerup state for the external device should

be compatible with the bootstrap state. If the powerup state is not compatible with the bootstrap

state, either select a different GPIO pin to control the external device or add additional circuitry to

reach the proper powerup state to the external device.

2 gpio[17] is used as both a bootstrap input pin for PLL_ND and an output that controls a power switch for

USB Host power. If the power switch needs to powerup in the inactive state, the enable to the power

switch must be the same value as the bootstrap value for PLL_ND; for example, if PLL_ND requires high on

gpio[17], a high true power switch must be selected. gpio[16] is used for USB_OVR and should have a

noise filter to prevent false indications of overcurrent, unless the USB power IC has this filter built in. See

“Example: Implementing gpio[16] and gpio[17]” on page 31 for an illustration.

3 The nFault signal GPIO6 or GPIO16 can be used as a code-controlled direction pin for the transceiver. The

polarity cannot be altered inside the NS9750B-A1; an inverter will be required.

Pin # Signal name

U/D

(mA)

I/O Descriptions (4 options: 00, 01, 02, 03)

Table 12: GPIO MUX pinout

1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 87 88

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