Digilent Parallel Interface Model Bedienungsanleitung PDF herunterladen

www.digilentinc.com

Revision: 08/10/2004

246 East Main | Pullman, WA 99163

(509) 334 6306 Voice and Fax

Introduction

The Digilent Communications Interface DLL, dpcutil.dll, provides a set of API functions for applications

programs running on a Microsoft Windows based computer to exchange data with logic implemented

in a Digilent system board. Various Digilent applications programs, such as Transport component of

the Adept Suite, depend on the data interchange API functions in dpcutil. The operation of these

functions depends on the presence of a Digilent communications subsystem component running the

appropriate firmware and the implementation of the appropriate interface logic in the gate array. This

document describes the functional requirements of the communications interface logic and provides a

sample implementation.

The logic described in this document implements are set of registers in the gate array. An application

on the host PC exchanges data with the design in the gate array by reading or writing these registers.

Digilent Communications Interface modules implement the interface described in this document to

control the reading and writing of these registers.

Functional Description

The Digilent Port Interface is patterned after the EPP mode of the parallel port interface on an IBM PC

type computer. This interface provides an 8 bit bi-directional parallel data bus and six handshaking

lines to control the data transfer. The actual data transfer speed that can be achieved depends on the

particular communications subsystem and firmware version being used.

The parallel port interface is made up of an eight bit wide address register and a set of eight bit wide

data registers. The address register holds the address of the data register currently being accessed.

Access to the registers is accomplished via transfer cycles. The four types of transfer cycles allowed

are: address read, address write, data read, and data write. Address read and address write cycles

read from or write to the address register. Data read and data write cycles read or write the data

The address register can be implemented with any number of bits up to the maximum size of eight

bits. Since the maximum size of the address register is eight bits, the maximum number of data

registers that can be implemented is 256. It isn’t necessary to implement all 256 possible data

registers. Only the registers needed for a particular application need to be implemented. It is

necessary for the application program using the interface to know which data registers are

implemented and what functions the implemented data registers perform.

Signal Descriptions

In the following description, the term host represents the host PC running the dpcutil application.

Signals sourced by the host are generated by the Digilent communication interface and are inputs to

the logic in the gate array. The term peripheral refers to the logic implemented in the gate array of the

system board. Signals sourced by the peripheral are outputs from the logic implemented in the gate

array.

The following signals make up the interface:

Name Source Description

DB0 – DB7 bidir Data bus. The host is the source during write cycles and the

peripheral is the source during read cycles.

WRITE host Transfer direction control. High = read, Low = write

1 2 3 4 5 6 ... 10 11

Inhaltsverzeichnis

Seite 1 - (509) 334 6306 Voice and Fax

DDiiggiilleenntt PPaarraalllleell IInntteerrffaaccee MMooddeell RReeffeerreennccee MMaannuuaall www.digilentinc.com Revision: 08/10/2004 246 Eas

Seite 2

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 10 end if; end process; ----

Seite 3

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 11 process (clkMain, regEppAdr, ctlEppDwr

Seite 4 - Data Read

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 2 ASTB host Address strobe. Causes data t

Seite 5 - Example Source Code:

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 3 Address Write DBWRITEASTBWAIT Address Re

Seite 6

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 4 Data Read DBWRITEDSTBWAIT

Seite 7

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 5 Example Source Code: The following is an

Seite 8

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 6 Port ( mclk : in std_logic;

Seite 9

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 7 signal ctlEppAstb : std_logic; sign

Seite 10

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 8 regData3 when regEppAdr = "

Seite 11

Digilent Parallel Interface Model Digilent, Inc. www.digilentinc.com Copyright Digilent, Inc. Page 9 stEppNext <= stEppAwrB;

Kommentare zu diesen Handbüchern

Keine Kommentare

Digilent Parallel Interface Model Bedienungsanleitung

Stöbern Sie online oder laden Sie Bedienungsanleitung nach Hardware Digilent Parallel Interface Model herunter. Digilent Parallel Interface Model User Manual [en] [de] [it] [fr] Benutzerhandbuch

Inhaltsverzeichnis

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Hardware Digilent Parallel Interface Model