Digital Signal Processing Reference
In-Depth Information
A larger Flash memory chip is typically used to boot the initial program code
on SoC designs that include a processor. Note that the older UP2 and UP1s
cannot support a Nios processor since they lack external memory and have a
smaller older FPGA. Links to detailed datasheets for many of the different
board's memory chips can be found on the topic's DVD or at the topic's
website.
Each board contains a crystal controlled clock circuit that is normally used as
the master clock for the user's digital logic circuit. Note that the frequency of
the clock is different on the boards as seen in table 2.1. PLLs can be used to
scale the crystal controlled clock to provide other clock frequencies.
2.3 The FPGA Board's I/O Features
Each board provides a wide variety of I/O features as summarized in Table 2.2.
For most devices, the FPGA board's hardware provides only an electrical
interface to the FPGA's I/O pins. Logic that provides a device interface circuit
or controller will need to be constructed by the user using the FPGA's internal
logic. Many design examples of interfacing to these various I/O devices can be
found in the following chapters of this topic.
Standard 0.1 inch headers on each of the boards can be used to interface to
external devices off of the board. A small custom PCB can be designed or a 0.1
inch predrilled perforated protoboard can be used to plug into the header
connectors on the board. Standard 0.1 inch ribbon cable connector technology
can also be used to connect to another board with custom user hardware.
Table 2.2 The I/O Features of the different development boards.
I/O Features
DE1
DE2
UP3
UP1& 2
Pushbuttons
4 debounced
4 debounced
2 -no debounce
4 -no debounce
User Switches
18
10
4
8
User LEDs
8 green 10 red
9 green 18 red
4
No
LCD Panel
No
16 char x 2 line
16 char x 2 line
No
4
8
No
2
Seven Segment
LED Displays
PS/2
Yes
Yes
Yes
Yes
RS-232 Serial
Yes
Yes
Yes
No
VGA output
2
12
colors
2
30
colors
8 colors
8 colors
I/O Expansion
Header Pins
2 - 40 Pin
connectors
2 - 40 Pin
connectors
4 - 72 I/O Pins
total
3 - add 60 Pin
headers
TV Decoder
No
Yes
No
No
SD Card slot
Yes
Yes
No
No
Printer Port
No
No
Yes
No
Audio CODEC
24bit
24bit
No
No
User USB
No
Yes
No
No
IrDA
No
Yes
No
No
Network
No
10/100Mhz
No
No
Yes
Yes
No
No
Optional Camera
and Color LCD
Panel
