DOC PREVIEW
MSU PHY 440 - Digilab DIO1 Reference Manual

This preview shows page 1-2-3 out of 10 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 10 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 10 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 10 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 10 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Copyright Digilent, Inc. All rights reserved Document: 502-009 Digilab DIO1 Reference Manual Revision: May 7, 2002 Overview The Digilab Digital I/O board 1 (DIO1) is one of several expansion boards designed to mate with Digilab system boards. The DIO1 is an inexpensive board that contains an assortment of basic digital I/O devices, including buttons, switches, and several LED displays. The DIO1 board can be combined with Digilab system boards to provide a source of ready-made I/O devices, allowing a wide range of projects to be implemented without the need for any other components. DIO1 board features include: • A four digit seven-segment LED display; • 8 individual LEDs; • A 3-bit VGA port; • 4 momentary pushbuttons; • 8 slide switches; • A PS2 mouse/keyboard port. Functional description The DIO1 board has been designed to provide a basic, inexpensive platform that contains many of the I/O devices commonly found in digital systems. Unlike the more advanced DIO2 board, the DIO1 board has been designed so that all signals pass directly to an attached system board, so no intermediate logic is required. When mated with a Digilab system board, the DIO1 board can provide a flexible prototyping system that can be operational immediately. Digilent, Inc. 125 SE High Street Pullman, WA 99163 (509) 334 6306 (Voice and Fax) www.digilentinc.com PRELIMINARY 8 LEDs4 displays 8 switchesPS2portConnector B254 buttons74HC373LatchConnector A12489VGA Port Figure 1. DIO1 schematicDigilab DIO1 Reference Manual Digilent, Inc. Rev: May 7, 2002 www.digilentinc.com Page 2 of 10 Signals All named signals used on the DIO1 board are defined in the table on the right. Voltage levels for all signals arriving from an attached Digilab system board are determined by the system board, but all signals arising on the I/O board derive from the on-board 5VDC regulator (so they are all 5V CMOS signals). The DIO1 board uses a two-layer process, so all signals are available on the top and bottom layers. Many signals are brought to a test point header for easy test and measurement equipment attachment. Power Supply The DIO1 board receives system power from pins 39 and 37 of connectors A and B (which mate to pins 1 and 3 of an attached system boards). Pin 37 provides Vdd from the attached system board (assumed to be 3.3VDC), and pin 39 is connected to ground. Up to 5VDC can be safely applied to the Vdd input pin (pin 37). The DIO1 board typically consumes less than 10mA with no LED’s illuminated, and up to 130mA with all LEDs illuminated (including all segments of the seven-segment display). LEDs Eight LEDs are provided for circuit outputs. The LED cathodes are tied to ground via 270-ohm resistors, and the anodes are driven from the 74HC373 (so the LED drive signals are active high). Seven-segment LED display The DIO1 board contains a modular 4-digit, common anode, seven-segment LED display. In a common anode display, the seven anodes of the LEDs forming each digit are connected to four common circuit nodes (labeled AN1 through AN4 on the DIO1 board). Each anode, and therefore each Power Supplies VU Unregulated power supply voltage from attached system board – typically 5-9VDC. Although connected to the board, this supply is not used on the DIO1 board. VDD33 Regulated power supply voltage (3.3VDC) from attached system board. All devices on DIO1 board use this supply. GND System ground VGA signals HS VGA Horizontal Sync signal VS VGA Vertical Sync signal R VGA 1-bit red data G VGA 1-bit green data B VGA 1-bit blue data PS2 signals KCLK PS2 (Keyboard or Mouse) clock signal KDAT PS2 (Keyboard or Mouse) data signal Input devices BTN1-4 Pushbuttons 1 through 4 SW1-SW8 Slide switches 1 through 8 Output devices LD0-LD8 Discreet LEDs 1 through 8 CA-CF Seven-segment display cathodes AN1-AN3 Seven-segment display anodes Table 1. DIO1 board signal definitions IC174HC373LD signalsGNDGNDLD1- LD8RP1270 OhmRP810K OhmD QGLDG signalGNDRP810K OhmDigilab DIO1 Reference Manual Digilent, Inc. Rev: May 7, 2002 www.digilentinc.com Page 3 of 10 digit, can be independently turned on and off by driving these signals to a ‘1’ or a ‘0’. The cathodes of similar segments on all four displays are also connected together into seven common circuit nodes labeled CA through CG. Thus, each cathode for all four displays can be turned on and off independently. Figure 4. (a) Seven segment display detail.(b) common anode display configuration. (c)segement illumination patterns for decimal.digits. (d) segment illumination truth table.Common anode Digit Illuminated SegmentShowna b c d e f g 01 1 1 1 1 1 0 1 0 1 1 0 0 0 0 21 1 0 1 1 0 1 3 1 1 1 1 0 0 1 40 1 1 0 0 1 1 51 0 1 1 0 1 1 61 0 1 1 1 1 1 71 1 1 0 0 0 0 81 1 1 1 1 1 1 91 1 1 1 0 1 1afedcbga f g e d c b(a) (b)(c)(d) This connection scheme creates a multiplexed display, where driving the anode signals and corresponding cathode patterns of each digit in a repeating, continuous succession can create a 4-digit display. In order for each of the four digits to appear bright and continuously illuminated, all four digits should be driven once every 1 to 16ms (for a refresh frequency of 60Hz to 1KHz). For example, in a 60Hz refresh scheme, each digit would be illuminated for ¼ of the refresh cycle, or 4ms. The controller must assure that the correct cathode pattern is present when the corresponding anode signal is driven. To illustrate the process, if AN1 is driven high while CB and CC are driven low, then a “1” will be displayed in digit position 2. Then, if AN2 is driven high while CA, CB and CC are driven low, then a “7” will be displayed in digit position 2. If AN1/CB, CC are driven for 4ms, and then AN2/CA, CB, CC are driven for 4ms in an endless succession, the display will show “17” in the first two digits. An example timing diagram is provided to the right. a1Cathodes -- connected toCPLD pins via 100Ω resistorAnodes -- connected to CPLDvia transistors for greater currentVddabc d e f g dpa2a3a4 AN1AN2AN3AN4CathodesDigit 1 Digit 2 Digit 3 Digit 4Refresh period = 1ms to 16msDigit period = Refresh / 4 Seven segment display refresh signals and timingsDigilab DIO1 Reference Manual Digilent, Inc. Rev: May 7, 2002 www.digilentinc.com Page 4 of 10 Pushbuttons Outputs from the 4 momentary-contact push buttons are normally low, and


View Full Document

MSU PHY 440 - Digilab DIO1 Reference Manual

Documents in this Course
qst

qst

42 pages

PLD_I

PLD_I

14 pages

AD624_c

AD624_c

15 pages

l15

l15

5 pages

Load more
Download Digilab DIO1 Reference Manual
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Digilab DIO1 Reference Manual and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Digilab DIO1 Reference Manual 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?