User manual

A&D Board User Manual and Test Procedure

It is common practice to connect each power source to a breadboard bus. The busses are

labeled with a red line to represent the ‘+’ busses and a blue line to represent the ‘-‘ busses.

These busses provide a convenient and effective method to distribute power to your circuit

For advanced users, the raw power supplied to the board by the wall adapter is available in

the socket headers labeled “+12V Raw” and “-12V Raw”.

B) Digital Logic Probes

The 16 logic probes are compatible with the 74HC logic family. The slide switch disables the

LED indicators, when desired.

There are 2 logic probe socket headers, labeled 1-8 and 9-16. Each header has two rows of 8

columns, to indicate 2 functionally identical sockets for each signal input. Each column has a

white line between a header column and a bi-polar LED as a visual aid.

Each logic probe input connects to a circuit, which compares logic levels 60 times a second.

When the logic probe switch is ON, a bi-polar LED displays the output of this comparison

circuit.

When an input is at a HIGH (or 1) logic state, the corresponding LED will light RED. When

an input is at a LOW (or 0) logic state, the corresponding LED will light GREEN. If the input

is changing state, the LED color will fluctuate in concert.

When an input is not connected to an external circuit, it can be affected by very low input

currents, and the LED-s may flicker. This indicates an indeterminate logic state. For fun, run

your finger along the top of the socket headers.

C) Digital Switches

The 16 digital switch outputs are buffered and compatible with the 74HC logic family.

There are two digital switch socket headers, labeled 1-8 and 9-16. Each header has two rows

of 8 columns, to indicate 2 functionally identical sockets for each output signal. Each column

has a number between a socket and its corresponding switch.

There are two "dual inline package" (DIP) switches, labeled 1-8 and 9-16. Each switch is

labeled LO (= ON) and HI (= OFF). When a switch is in the LO position, the corresponding

socket will output a logic LOW (or 0). When a switch is in the HI position, the corresponding

socket will output a logic HIGH (or 1).

CAUTION: Do not use a pencil to change the switch positions. Pencil "lead" is conductive

and will destroy your switch. A retracted ballpoint pen works well.

D) Digital Pulsers

There are two digital pulsers, with identical functionality, labeled "A" and "B". These pulsers

are compatible with the 74HC logic family. Each pulser output connects to a 4 row by 2

column socket header.

The top two rows, of each socket header, are labeled with a "down arrow" and the bottom

two rows are labeled with a "up arrow". This gives you 4 possible connections to either

function.

The "down arrow" indicates that pushing the momentary push button will cause the output to

change to a LOW (or 0) state, only while the button is pushed. When the push button is

released, the output returns to a HIGH (or 1) state. The pulser is de-bounced, so there is only

one logic transition pulse per button push.