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2.3

Configuration of Pullup Resistors for Pins 8, 9, and 10

2.4

EEPROM

2.5

LED Indication of USB Attached

Configuration of Pullup Resistors for Pins 8, 9, and 10

The pullups for pins 8, 9, and 10 (see the schematic in Chapter 6) are configurable through

communications with the embedded firmware in the TUSB3210 (see the command Set Pullup Resistors in

Chapter 3). The default setting is for all these three pins to have pullups of 2.2 k

Ω. Table 2-2 lists the

possible options for each pin.

Table 2-2. Configurable Options of Pullup Resistors for Pins 8, 9, and 10

PULLUP RESISTOR

OPTION 1

OPTION 2

OPTION 3

OPTION 4

OPTION (BYTE VALUE)

(0x00)

(0x01) (DEFAULT)

(0x02)

(0x03)

Pin 8 of J2: ALERT line

No pullup (open)

2.2 k

Ω

N/A

Pin 9 of J2: CLOCK line

No pullup (open)

2.2 k

Ω

1 k

Ω

688

Ω

Pin 10 of J2: DATA line

No pullup (open)

2.2 k

Ω

1 k

Ω

688

Ω

The embedded firmware is stored in a 64-Kbits EEPROM (see U1 in the schematic in Chapter 6). The

firmware is field programmable (see Chapter 5 for more information). Jumper shunt J1 is normally closed

and is used for firmware development only. On power up, the TUSB3210 downloads the firmware image

from the EEPROM to the internal static RAM and starts firmware execution (first with USB enumeration)

from there.

A green LED is mounted next to the USB connector on the evaluation board. Every time the USB interface

adapter is attached to a PC via a USB cable, and if the host PC detects it and goes through USB

enumeration successfully, the embedded firmware illuminates the green LED (D1) to indicate that;

otherwise, the LED remains off. After unplugging the USB cable, the LED turns off immediately.

Summary of Hardware Design

SLLU093 – August 2006

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