TC1796
System Units (Vol. 1 of 2)
Introduction
User’s Manual
1-2
V2.0, 2007-07
Intro, V2.0
•
Functional units of the TC1796 are given in plain UPPER CASE. For example: “The
EBU provides an interface to external peripherals”.
•
Pins using negative logic are indicated by an overline. For example: “The external
reset pin, HDRST, has a dual function.”.
•
Bit fields and bits in registers are in general referenced as “Register name.Bit field”
or “Register name.Bit”. For example: “The Current CPU Priority Number bit field
ICR.CCPN is cleared”. Most of the register names contain a module name prefix,
separated by a underscore character “_” from the real register name (for example,
“ASC0_CON”, where “ASC0” is the module name prefix, and “CON” is the kernel
register name). In chapters describing the kernels of the peripheral modules, the
registers are mainly referenced with their kernel register names. The peripheral
module implementation sections mainly refer to the real register names with module
prefixes.
•
Variables used to describe sets of processing units or registers appear in mixed
upper-and-lower-case font. For example, register name “MSGCFGn” refers to
multiple “MSGCFG” registers with variable n. The bounds of the variables are always
given where the register expression is first used (for example, “n = 31-0”), and are
repeated as needed in the rest of the text.
•
The default radix is decimal. Hexadecimal constants are suffixed with a subscript
letter “H”, as in 100
H
. Binary constants are suffixed with a subscript letter “B”, as in
111
B
.
•
When the extent of register fields, groups of signals, or groups of pins are collectively
named in the body of the document, they are given as “NAME[A:B]“, which defines a
range for the named group from B to A. Individual bits, signals, or pins are given as
“NAME[C]” where the range of the variable C is given in the text. For example:
CFG[2:0], and SRPN[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
= 1048576 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 .000001. For example, 1 Kbyte is
1024 bytes, 1 Mbyte is 1024 x 1024 bytes, 1 kBaud/kbit are 1000 characters/bits
per second, 1 MBaud/Mbit are 1000000 characters/bits per second, and 1 MHz is
1,000,000 Hz.
•
Data format quantities are defined as follows:
–
Byte
= 8-bit quantity
–
Half-word
= 16-bit quantity
