Digilent Ceres - Manual

D D i i g g i i l l e e n n t t C C e e r r e e s s R R e e f f e e r r e e n n c c e e M M a a n n u u a a l l TM
w w w . d i g i l e n t i n c . c o m
Revision: August 11, 2005 246 East Main | Pullman, WA 99163
(509) 334 6306 Voice and Fax
© Digilent, Inc. 4 pages Doc: 502-048
Overview
The Ceres board provides a ready-made
development platform for Digilent C-Mod
boards. It contains a 40-pin DIP socket to hold
C-Mods, and a collection of useful I/O devices
connected to the socket pins. The Ceres/C-
Mod board combination makes an ideal
platform for students or engineers who want to
experiment with modern design technologies
and/or Xilinx CPLD devices. The Ceres board
can operate from a wall-plug power supply
(included), or up to 40 hours on two AA
batteries. Ceres features include:
•
An user-settable oscillator (0.5Hz - 4KHz);
•
4-digit, high-bright seven-segment display;
•
4 debounced buttons and 8 slide switches;
•
8 LEDs in three different colors (red, green,
and yellow);
•
40-pin Dip format receptacle for use with
the C-Mod line of boards;
•
40-pin expansion connector capability.
•
Attached C-Mod boards can be
programmed with JTAG3 cable.
The Ceres/C-Mod board makes an excellent
platform for introducing programmable
technologies in instructional lab settings. The
C-mod boards can host a wide range of
designs, from simple logic circuits to complex
state machines. The CPLDs use non-volatile
configuration memory, so designs can be
completed outside the lab and brought in for
evaluation. The Ceres/C-mod combination is
fully compatible with all versions of the Xilinx
CAD tools, including the free WebPack tools
available at the Xilinx website. When
purchased in combination, the Ceres/C-Mod
ships with a programming cable and a power
source, so designs can be implemented
immediately without the need for any additional
hardware.
Functional description
The Ceres board provides a power supply and
collections of I/O devices that can be used by
C-Mod boards. Ceres boards can host different
C-Mod boards, so designs can easily be
retargeted to different CPLD devices for
experimentation. Current C-Mod boards
include the C-Mod 95 (XC9572XL), the C-Mod
C2 (XC2C64), and the C-Mod XCR
(XCR3064XL).
The Ceres board can be powered from a wall-
plug power supply or from a 2AA battery pack.
A 40-pin expansion connector makes all DIP
connector signals available to external circuits.
Ceres/C-Mod JTAG Configuration
C-Mod boards contain a JTAG port for
programming, but the Ceres board does not.
The C-Mod JTAG port consists of a pattern of
six offset holes that are not normally loaded
with header pins. A row of 6 unattached
header pins can be inserted into the end of a
JTAG3 cable, and the other side of the header
can be inserted into the offset hole patterns.
Expansion
Connector
C-Mod Board Socket
40-pin 600-mil DIP
Adjustable clock
(0.5Hz to 4KHz)
8 switches
8 LEDs
Four 7-seg.
displays
4 buttons
Debounce
Power/Battery
Jack
Figure 1. Ceres Block Diagram