Chapter 4

Module Descriptions

This chapter describes in alphabetical order the different types of modules, their connections, and their attributes. Each module represents a common logic function and is described in detail.

NOTE

The pin and attribute names in the following module descriptions are given in the following format: Carry Input (C_IN). The first name is how the pin or attribute is listed in the GUI module. The second name, in parentheses, is how the pin or attribute is listed in the .mod file. If only one name is listed, then the name is the same in both places.

The following list divides the different LogiBLOX modules into functional categories and briefly summarizes each module.

Arithmetic

ACCUMULATOR - Adds data to or subtracts it from the current value stored in the accumulator register.
ADDER/SUBTRACTER - Adds or subtracts two data inputs and a Carry input.
COMPARATOR - Compares the magnitude or equality of two values.
COUNTER - Generates a sequence of count values.

Logic

CONSTANT - Forces a constant value onto a bus.
DECODER - Activates 1-of-n lines on the output port, based on the input address.
MULTIPLEXER: Type 1, Type 2 - Routes 1-of-n input data lines to the output port.
SIMPLE GATES: Type 1, Type 2, Type 3 - Implements the AND, INVERT, NAND, NOR, OR, XNOR, and XOR logic functions.
TRISTATE BUFFER - Creates a tristated internal data bus.

I/O

INPUT/OUTPUT - Connects internal and external pin signals.
PAD - Represents an input/output pad.

Sequential

CLOCK DIVIDER - Generates a clock pulse whose period is a multiple of the clock input period.
COUNTER - Generates a sequence of count values.
SHIFT REGISTER - Shifts input data bits to the left or right.

Storage

DATA REGISTER - Captures the input data on active Clock transitions.
MEMORY: ROM, RAM, SYNC_RAM, DP_RAM - Stores information and makes it readable.
SHIFT REGISTER - Shifts input data bits to the left or right.