RAM 4.5 BUX II Series Manual de usuario descargar pdf (Pagina 28)

DE1 User Manual

FPGA

USB Blaster Circuit

EPCS4

Serial

Configuration

Device

JTAG Config Port

USB

Auto

Power-on Config

MAX

3128

Quartus II

Programmer

AS Mode

RUN/PROG

AS Mode

Config

"PROG"

Figure 4.2. The AS configuration scheme.

In addition to its use for JTAG and AS programming, the USB Blaster port on the DE1 board can

also be used to control some of the board's features remotely from a host computer. Details that

describe this method of using the USB Blaster port are given in Chapter 3.

4.2 Using the LEDs and Switches

The DE1 board provides four pushbutton switches. Each of these switches is debounced using a

Schmitt Trigger circuit, as indicated in Figure 4.3. The four outputs called KEY0, …, KEY3 of the

Schmitt Trigger device are connected directly to the Cyclone II FPGA. Each switch provides a high

logic level (3.3 volts) when it is not pressed, and provides a low logic level (0 volts) when

depressed. Since the pushbutton switches are debounced, they are appropriate for use as clock or

reset inputs in a circuit.

Figure 4.3. Switch debouncing.

There are also 10 toggle switches (sliders) on the DE1 board. These switches are not debounced,

and are intended for use as level-sensitive data inputs to a circuit. Each switch is connected directly

to a pin on the Cyclone II FPGA. When a switch is in the DOWN position (closest to the edge of

the board) it provides a low logic level (0 volts) to the FPGA, and when the switch is in the UP

position it provides a high logic level (3.3 volts).

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RAM 4.5 BUX II Series Manual de usuario Pagina 28