Freescale Semiconductor
2-1
Chapter 2
Signal Descriptions
2.1
Introduction
This chapter describes the external signals on the device. It includes an alphabetical signal listing of signals
that characterizes each signal as an input or output, defines its state at reset, and identifies whether a
pull-up resistor should be used.
NOTE
The terms assertion and negation are used to avoid confusion when dealing
with a mixture of active-low and active-high signals. The term asserted
indicates that a signal is active, independent of the voltage level. The term
negated indicates that a signal is inactive.
Active-low signals, such as SD_SRAS and TA, are indicated with an
overbar.
2.2
Signal Properties Summary
The below table lists the signals grouped by functionality.
NOTE
In this table and throughout this document, a single signal within a group is
designated without square brackets (i.e., FB_AD23), while designations for
multiple signals within a group use brackets (i.e., FB_AD[23:21]) and is
meant to include all signals within the two bracketed numbers when these
numbers are separated by a colon.
NOTE
The primary functionality of a pin is not necessarily its default functionality.
Most pins that are muxed with GPIO default to their GPIO functionality. See
Table 2-1
for a list of the exceptions.
Table 2-1. Special-Case Default Signal Functionality
Pin
256 MAPBGA
360 TEPBGA
FB_AD[31:0]
FB_AD[31:0] except when serial boot selects 0-bit
boot port size.
FB_BE/BWE[3:0]
FB_BE/BWE[3:0]
FB_CS[3:1]
FB_CS[3:1]
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...