USBN9604SLB datasheet(8/60 Pages) NSC

8 / 60 page

1.0 Signal/Pin Connection and Description (Continued)

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External Elements

Choose C1 and C2 capacitors (see Figure 1) to match the crystal’s load capacitance. The load capacitance CL “seen” by

the crystal is comprised of C1 in series with C2, and in parallel with the parasitic capacitance of the circuit. The parasitic

capacitance is caused by the chip package, board layout and socket (if any), and can vary from 0 to 8 pF. The rule of thumb

in choosing these capacitors is:

CL = (C1*C2)/(C1+C2)+C Parasitic

Figure 1. Typical Oscillator Circuit

1.2.3

USB Port

1.2.4

Microprocessor Interface

Resistor R2

ΝΑ

Capacitor C1

15 pF

±20%

Capacitor C2

15 pF

±20%

I/O

Name

Description

I/O

D+

USB D+ Upstream Port. This pin requires an external 1.5k pull-up to 3.3V to signal full speed

operation.

I/O

D–

USB D– Upstream Port

I/O

Name

Description

MODE1-0

Interface Mode. Each of these pins should be hard-wired to VCC or GND to select the inter-

face mode:

MODE1-0 = 00. Mode 0: Non-multiplexed parallel interface mode

MODE1-0 = 01. Mode 1: Multiplexed parallel interface mode

MODE1-0 = 10. Mode 2: MICROWIRE interface mode

MODE1-0 = 11. Mode 3: Reserved

Note: Mode 3 also selects the MICROWIRE interface mode in the USBN9602, but this mode

should be reserved to preserve compatibility with future devices.

DACK

DMA Acknowledge. This active low signal is only used if DMA is enabled. If DMA is not used,

this pin must be tied to VCC.

DRQ

DMA Request. This pin is used for DMA request only if DMA is enabled.

INTR

Interrupt. The interrupt signal modes (active high, active low or open drain) can be config-

ured via the Main Control register. During reset, this signal is TRI-STATE.

Chip Select. Active low chip select

Read. Active low read strobe, parallel interface

Component

Parameters

Values

Tolerance

XIN

XOUT

XTAL

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