Motorola DSP56012 - Manual (Page 25)

Overview
Introduction
MOTOROLA DSP56012 User’s Manual 1-5
1.1.2 Manual Conventions
The following conventions are used in this manual:
• The word “reset” is used in three different contexts in this manual. There is a
reset pin that is always written as “RESET”, there is a reset instruction that is
always written as “RESET”, and the word reset, used to refer to the reset
function, is written in lower case (with a leading capital letter as grammar
dictates.)
• Bits within a register are indicated AA[n:0] when more than one bit is
involved in a description. For purposes of description, the bits are presented
as if they are contiguous within the register; however, this is not always the
case. Refer to the programming model diagrams or to the programming sheets
to see the exact location of bits within a register.
• When a bit is described as “set”, its value is 1. When a bit is described as
“cleared”, its value is 0.
• Hex (hexadecimal) values are indicated with a dollar sign ($) preceding the
hex value, as in “$FFFB is the X memory address for the Interrupt Priority
Register (IPR).”
• Code examples are displayed in a monospaced font, as shown in
Example 1-1 .
• Pins or signals listed in code examples that are asserted low have a tilde (~) in
front of their names.
• The word “assert” means that a high true (active high) signal is pulled high (to
V
CC
) or that a low true (active low) signal is pulled low (to ground).
• The word “deassert” means that a high true signal is pulled low (to ground) or
that a low true signal is pulled high (to V
CC
).
• Overbars are used to indicate a signal that is active when pulled to ground
(see Table 1-1 ). For example, the RESET pin is active when pulled to ground.
Therefore, references to the RESET pin will always have an overbar. Such pins
and signals are also said to be “active low” or “low true.”
Example 1-1 Sample Code Listing
movep #0,x:EOR0 ; drive 2nd read trigger
bset #ERTS,x:ECSR ; set read triggers by reading EDDR
do #(N-2),end_OL ; loop to drive more (N-2) triggers