AN2798 Freescale Semiconductor / Motorola, AN2798 Datasheet

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AN2798

Manufacturer Part Number
AN2798
Description
Migrating from the MPC855T to the MPC885
Manufacturer
Freescale Semiconductor / Motorola
Datasheet
Freescale Semiconductor
Application Note
Migrating from the MPC855T to the MPC885
by
This document contains summary information that is useful when
migrating from the MPC855T to the MPC885. For more detailed
information, refer to the MPC885 PowerQUICC Family
Reference Manual and MPC885/MPC880 Hardware
Specifications (for the MPC885), and the MPC855T
PowerQUICC Family Users Manual and MPC860 Hardware
Specifications (for the MPC855T).
1 Overview
The need for embedded security and an additional Fast Ethernet
channel makes the transition from an MPC855T to an MPC885 a
logical progression. Both processors contain the same embedded
architecture-based core and system integration unit (SIU) to ease
software migration.
The MPC885 has twice the internal L1 cache as the MPC855T for
a total of 8 Kbytes for data and 8 Kbytes for instructions. The
MPC885 has a faster core and faster bus speed than the MPC855T.
The MPC885 incorporates four 16-bit timers that can be cascaded
into two 32-bit timers.
The MPC885 incorporates two Fast Ethernet channels instead of
one and has a similar CPM. However, the variety of serial
channels has changed. While both the MPC855T and the MPC885
feature UTOPIA, the MPC885 can support full duplex UTOPIA
© Freescale Semiconductor, Inc., 2004. All rights reserved.
Eric Jackson
NCSD Applications
Freescale Semiconductor, Inc.
Austin, TX
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Feature Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. The MPC885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. The MPC855T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Similarities and Differences between the MPC855T and the
6. New Features for MPC885 . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
MPC885 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Contents
Rev. 0, 10/2004
AN2798

Related parts for AN2798

AN2798 Summary of contents

Page 1

... CPM. However, the variety of serial channels has changed. While both the MPC855T and the MPC885 feature UTOPIA, the MPC885 can support full duplex UTOPIA © Freescale Semiconductor, Inc., 2004. All rights reserved. AN2798 Rev. 0, 10/2004 Contents 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 ...

Page 2

Feature Comparison and Fast Ethernet simultaneously. The MPC885 also has a USB 1.1 controller and an on-chip security processor that can perform encryption on the serial channels and TDM interface. Figure 1 and Figure 2 show block diagrams for MPC885 ...

Page 3

The MPC885 The MPC885 PowerQUICC™ 0.18 µm version of the MPC860 PowerQUICC family of communications microprocessors. Unlike the MPC855T, the MPC885 has a core voltage of 1.8 V and an I/O voltage of 3.3 V, with 5V-input ...

Page 4

The MPC855T 4 The MPC855T The MPC855T PowerQUICC is a 0.32 µm version of the MPC8XX PowerQUICC family of communications microprocessors. The MPC855T has a core voltage of 3.3 V and an I/O voltage of 3.3 V, with 5V-compatibility. The ...

Page 5

Pinout Both the MPC855T and the MPC885 use the 357 plastic ball grid array (PBGA) package. Buses and other functions were grouped in a logical order, but reuse of layout is not available. Parallel ports changed from four (Port ...

Page 6

Similarities and Differences between the MPC855T and the MPC885 Figure 4 shows the MPC855T pinout. NOTE: This is the top view of the device. PD10 PD8 PD3 IRQ7 PD14 PD13 PD9 PD6 M_Tx_EN PA0 PB14 PD15 PD4 PD5 PA1 PC5 ...

Page 7

Reserved space (offset 0xA20-0xA77) in the MPC855T is now for SCC2 and SCC3 in the MPC885. • Port E registers in the MPC885 reside in a previously reserved area of the Port B registers in the MPC855T (starting at ...

Page 8

New Features for MPC885 6.2 Digital Phase Lock Loop The MPC885 features a digital phase lock loop (DPLL). The main purpose of the DPLL is to generate a stable reference frequency by multiplying the frequency and eliminating the clock skew. ...

Page 9

Summary Although the migration from the MPC855T to the MPC885 requires layout and software changes, the benefits of an additional Fast Ethernet controller, USB 1.1, and an internal security engine may warrant the migration, depending on system requirements. Migrating ...

Page 10

Summary THIS PAGE INTENTIONALLY LEFT BLANK Migrating from the MPC855T to the MPC885, Rev Freescale Semiconductor ...

Page 11

THIS PAGE INTENTIONALLY LEFT BLANK Migrating from the MPC855T to the MPC885, Rev. 0 Freescale Semiconductor Summary 11 ...

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... Tai Po Industrial Estate Tai Po, N.T. Hong Kong 852-26668334 Home Page: www.freescale.com AN2798 Rev. 0 10/2004 Information in this document is provided solely to enable system and software implementers to use Freescale Semiconductor products. There are no express or implied copyright licenses granted hereunder to design or fabricate any integrated circuits or integrated circuits based on the information in this document ...

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