Rev. 7/15/2004

© Copyright 2004 Sipex Corporation

APPLICATION NOTE

Processors in the Motorola MPC850 PowerQUICC™ family support one USB host port at a

12Mbit/sec data rate. They require an external USB transceiver, such as the SP5301, to

provide the analog interface to the Universal Serial Bus.

Motorola

MPC850

PowerQUICC

12Mbps

USB

Host

Controller

48MHz Ref. Clock

/OE

SUSPND

VM

VP

RCV

GND

VMO

SPEED

D-

D+

VPO

Vcc

SIPEX

SP5301

USBOE# (14)

USBRXM (10)

USBRXD (15)

USBRXP (11)

USBTXN (6)

USBTXP (7)

Vcc =

+3.3V

GND

D-

D+

V_BUS

V_BUS =

+5V

USB

Connector

Vcc =

+3.3V

Not shown:

0.1uF Bypass capacitor on Vcc

Float RERR and RSE0 (No Connect)

22

ohm

1.5K

RERR

RSE0

NC

NC

The USB controller on the MPC850 uses six signals. Additional signals such as SUSPEND and

SPEED can be driven using general purpose outputs if desired.

Signal

MPC

Dir

Signal

SP5301

Function

USBTXN

→

VMO

USBTXP

→

VPO

Data outputs from Host, Inputs to Transceiver,

Driven onto D- and D+

USBOE#

→

OE#

Output Enable, controls SP5301 transmit or receive

USBRXD

←

RCV

Differential Receive

USBRXP

←

VP

USBRXN

←

VM

Single Ended Receive. Gated version of D+ and D-. Used to

detect Single-ended Zero (EOF and Reset)

→

SUSP

Drive high to put SP5301 into low power state

→

SPEED

Drive low to adjust driver slew rate for Low Speed (1.5Mbps)

←

RERR

Outputs high if D+ and D- are 11 (illegal state).

Leave unconnected if not used

Optional

Signals

←

RSE0

Outputs high if D+ and D- are 00 (SE0).

Leave unconnected if not used

Connecting SP5301 to MPC850 PowerQUICC™