Module 2 – Digital I/O

Output: Use the digital port to provide signals to display a number on a seven segment light emitting display (LED) display by wiring up the breadboard to connect it to the 8 port0 digital lines. • Test this interface with a VI that lets you enter a number on the

front panel and then displays the number on the seven- segment LED. The VI should turn the LED’s off when it quits.

Input: Use the same portm in input mode, to read a binary pattern created by setting the switches on a dual in-line package (DIP) switch module, and mount the device on the breadboard and connect it to the same 8 digital lines.. • Test this interface with another (or part of the previous) VI.

Physics 434 1

Physics 434 2

Notes on Module 2

• Two VI’s, due next week. – (Note that you can combine them into one, using a listbox or ring )– TTL output logic levels: <0.4 V off, > 4.35 V on.– Input: open means off, closed (connected to 5 V) on.

• Use 8 300 current-limiting resistors.• Note that same 8 lines are output (part I) and input (part II).

– You can set up your breadboard to do both• You have to deal with binary numbers (table II is a worksheet)

– Note the Format & Precision menu item for a numeric constant, which can be used to set binary (or octal or hexadecimal).

• Note the requirement: your VI should turn the LED’s off when it stops. (think about how to do it.)

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Seven segment wiring (common cathode)

A 14

B 13

C 8

D 7

E 6

F 1

G 2

dp 9

Cath 4,12

DIPs (Dual-Inline-Packages) have an orientation notch in one end. If the chip is held so that the long axis is horizontal and the notch is at the left end, pin #1 is the leftmost pin in the bottom row. Pins are numbered counter-clockwise from there, i.e. left to right across the bottom row, then right to left across the top row. This allows automated chip-insertion machinery to ensure correct orientation of the chip by mechanical sensing. The picture is for a 8-pin DIP. In this case the “notch” is the top.

Wiring of the CAT5 pairs and 7-seg.

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Data Color DAQ header

7-seg pin

7-seg

name

P0.0 brown 65 1 14 A

P0.1 “/white 66 2 13 B

P0.2 orange 67 3 8 C

P0.3 “/white 68 4 7 D

P0.4 green 69 5 6 E

P0.5 “/white 70 6 1 F

P0.6 blue 71 7 2 G

P0.7 “/white 72 8 9 dec.pt

Gnd 4 or 12 Cath.

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Notes on mapping

• How do you convert the numbers 1-9 to a different sequence? In most languages, two choices:– case or if-elseif (adds code, complexity)– Table lookup (adds to memory)

• How does this map into G? See the Demo VI.