Freescale Semiconductor
Advance Information
Document Number: MC33781
Rev. 4.0, 7/2008
Quad DSI 2.02 Master with
Differential Drive and
Frequency Spreading
The 33781 is a master device for four differential DSI 2.02 buses.
It contains the logic to interface the buses to a standard serial
peripheral interface (SPI) port and the analog circuitry to drive data
and power over the bus, as well as receive data from the remote slave
devices.
The differential mode of the 33781 generates lower
electromagnetic interference (EMI) in situations where data rates and
wiring make this a problem. Frequency spreading further reduces
interference by spreading the energy across many frequencies,
reducing the energy in any single frequency.
Features
• Four independent differential DSI (DBUS) channels
• Dual SPI interface
• Enhanced bus fault performance
• Automatic message cyclical redundancy checking (CRC)
generation and checking for each channel
• Enhanced register set with addressable buffer allows queuing of 4
independent slave commands at one time for each channel
• 8- to 16-Bit messages with 0- to 8-Bit CRC
• Independent frequency spreading for each channel
• Pseudo bus switch feature on channel 0
• Pb-free packaging designated by suffix code EK
+5.0V
+25V
33781
DIFFERENTIAL DSI 2.02 MASTER
EK SUFFIX (PB-FREE)
98ASA10556D
32-PIN SOICW EP
ORDERING INFORMATION
Device
PCZ33781EK/R2
Temperature
Range (T
A
)
-40°C to 90°C
Package
32 SOICW EP
33781
VCC
SCLK
CS
VCC
SCLK0
CS0
MOSI0
MISO0
RST
CLK
0.1μF
SCLK1
MISO1
VDD
VSS_IDDQ
SCLK1
MISO1
CS1
AGND
GND
VSUP1
DPH
DPL
D0H
D0L
D1H
D1L
D2H
D2L
D3H
D3L
VSS
1.0μF
DBUS SLAVE
MCU1
MOSI
MISO
RST
CLK
GND
DBUS SLAVE
DBUS SLAVE
DBUS SLAVE
DBUS SLAVE
MCU2
GND
CS1
2.2nF capacitors from DOH, D0L,
D1H, D1L, D2H, D2L, D3H and D3L
to circuit ground are required for
proper operation
Figure 1. 33781 Simplified Application Diagram
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2007-2008. All rights reserved.
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
