IDT About This Manual
Documentation Conventions and Definitions
79RC32438 User Reference Manual
ii
November 4, 2002
Notes
Chapter 12, “General Purpose I/O Controller,”
describes this controller and how it is configured to
operate as a general purpose I/O or as an alternate function.
Chapter 13, “UART Controller,”
provides information about the two separate UARTs within the
RC32438, including the UART registers.
Chapter 14, “Counter Timers,”
describes the three general purpose 32-bit counter/timers on the
RC32438.
Chapter 15, “I
2
C Bus Interface,”
describes the standard I
2
C bus interface, supporting both master and
slave operations, that is implemented on the RC32438.
Chapter 16, “Serial Peripheral Interface,”
describes the SPI master interface which uses three signals
to connect to low-cost SPI peripherals and memory.
Chapter 17, “On-Chip Memory,”
describes the operation and support provided by on-chip memory for
memory read and write operations on the RC32438.
Chapter 18, “Debugging and Performance Monitoring,”
discusses the three different debugging
features available on the RC32438: IPBus Monitor, Event Monitor, and Debug Pins.
Chapter 19, “JTAG Boundary Scan,”
discusses an enhanced JTAG interface for low-cost In-Circuit
Emulation. This discussion includes a system logic TAP controller, signal definitions, a test data register, an
instruction register, and usage considerations.
Chapter 20,“EJTAG System,”
describes the EJTAG’s features, its Debug Control Register, TAP regis-
ters, EJTAG Probe, hardware breakpoints, and other related topics.
Documentation Conventions and Definitions
Throughout this manual the following conventions and terms are used:
To avoid confusion when dealing with a mixture of “active-low” and “active-high” signals, the terms
assertion and negation are used. The term assert or assertion is used to indicate that a signal is
active or true, independent of whether that level is represented by a high or low voltage. The term
negate or negation is used to indicate that a signal is inactive or false.
To define the active polarity of a signal, a suffix will be used. Signals ending with an ‘N’ should be
interpreted as being active, or asserted, when at a logic zero (low) level. All other signals (including
clocks, buses and select lines) will be interpreted as being active, or asserted when at a logic one
(high) level.
To define buses, the most significant bit (MSB) will be on the left and least significant bit (LSB) will
be on the right. No leading zeros will be included.
To represent numerical values, either decimal, binary, or hexadecimal formats will be used. The
binary format is as follows: 0bDDD, where “D” represents either 0 or 1; the hexadecimal format is
as follows: 0xDD, where “D” represents the hexadecimal digit(s); otherwise, it is decimal.
Unless otherwise denoted, a byte will refer to an 8-bit quantity. A halfword will refer to a 16-bit quan-
tity. A triple-byte will refer to a 24-bit quantity. A word will refer to a 32-bit quantity, and a double or
double word will refer to a 64-bit quantity.
A bit is set when its value is 0b1. A bit is cleared when its value is 0b0.
The compressed notation ABC[x|y|z]D refers to ABCxD, ABCyD, and ABCzD.
The compressed notation ABC[x..y]D refers to ABCxD, ABC(x+1)D, ABC(x+2)D, ... ABCyD.
In words, bit 31 is always the most significant bit and bit 0 is the least significant bit. In halfwords, bit
15 is always the most significant bit and bit 0 is the least significant bit. In bytes, bit 7 is always the
most significant bit and bit 0 is the least significant bit.
The ordering of bytes within words is referred to as either “big endian” or “l(fā)ittle endian.” Big endian
systems label byte zero as the most significant (leftmost) byte of a word. Little endian systems label
byte zero as the least significant (rightmost) byte of a word.