XC886/888CLM
Introduction
User’s Manual
1-18
V1.3, 2010-02
Introduction, V 1.1
1.5
Text Conventions
This document uses the following text conventions for named components of the
XC886/888:
•
Functional units of the XC886/888 are shown in upper case. For example: “The SSC
can be used to communicate with shift registers.”
•
Pins using negative logic are indicated by an overbar. For example: “A reset input pin
RESET is provided for the hardware reset.”
•
Bit fields and bits in registers are generally referenced as “Register name.Bit field” or
“Register name.Bit”. Most of the register names contain a module name prefix,
separated by an underscore character “_” from the actual register name. In the
example of “SSC_CON”, “SSC” is the module name prefix, and “CON” is the actual
register name).
•
Variables that are used to represent sets of processing units or registers appear in
mixed-case type. For example, the register name “CC6xR” refers to multiple
“CC6xR” registers with the variable x (x = 0, 1, 2). The bounds of the variables are
always specified where the register expression is first used (e.g., “x = 0 - 2”), and is
repeated as needed.
•
The default radix is decimal. Hexadecimal constants have a suffix with the subscript
letter “H” (e.g., C0
H
). Binary constants have a suffix with the subscript letter “B”
(e.g., 11
B
).
•
When the extents of register fields, groups of signals, or groups of pins are
collectively named in the body of the document, they are represented as
“NAME[A:B]”, which defines a range, from B to A, for the named group. Individual
bits, signals, or pins are represented as “NAME[C]”, with the range of the variable C
provided in the text (e.g., CFG[2:0] and TOS[0]).
•
Units are abbreviated as follows:
–
MHz
= Megahertz
–
µ
s
= Microseconds
–
kBaud, kbit
= 1000 characters/bits per second
–
MBaud, Mbit
= 1,000,000 characters/bits per second
–
Kbyte
= 1024 bytes of memory
–
Mbyte
= 1,048,576 bytes of memory
In general, the k prefix scales a unit by 1000 whereas the K prefix scales a unit by
1024. Hence, the Kbyte unit scales the expression preceding it by 1024. The
kBaud unit scales the expression preceding it by 1000. The M prefix scales by
1,000,000 or 1048576, and
µ
scales by 0.000001. For example, 1 Kbyte is
1024 bytes, 1 Mbyte is 1024
×
1024 bytes, 1 kBaud/kbit are 1000 characters/bits
per second, 1 MBaud/Mbit are 1,000,000 characters/bits per second, and 1 MHz
is 1,000,000 Hz.
•
Data format quantities are defined as follows:
–
Byte
= 8-bit quantity
*
