AN2798 Freescale Semiconductor / Motorola, AN2798 Datasheet - Page 2

• Manufacturer Part Number: AN2798
• Description: Migrating from the MPC855T to the MPC885
• Manufacturer: Freescale Semiconductor / Motorola

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
2 Feature Comparison
The MPC855T and the MPC885 communications microprocessors incorporate many types of communications
engines to accommodate different system requirements. The following sections discuss hardware and protocol
features of both microprocessors.
2.1 Hardware Features
Table 1
2.2 Protocol Features
Table 2
2
compares the MPC855T and the MPC885 hardware features.
compares the MPC855T and the MPC885 protocol features.
and
Figure 2
show block diagrams for MPC885 and MPC855T, respectively.
Core frequency (max)
Bus frequency (max)
I and D cache
FEC
Security
USB 1.1
Time slot assigner (TSA)
SPI
SMC
SCC
PCMCIA
10/100 Fast Ethernet
10BT Ethernet
HDLC/SDLC
UART
Transparent
Migrating from the MPC855T to the MPC885, Rev. 0
Protocol
Table 1. Hardware Features Comparison
Table 2. Protocol Feature Comparison
Feature
MPC855T
Yes
Yes
Yes
Yes
MPC855T
1
80 MHz
66 MHz
Yes
Yes
4K
No
No
1
1
2
1
MPC885
MPC885
133 MHz
Yes
Yes
Yes
Yes
80 MHz
2
Yes
Yes
Yes
Yes
8K
2
1
2
3
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