Specifications

120 Chapter 6—Primitive Devices
Hex Keyboard
The hex keyboard outputs the binary equivalent of a hexadecimal digit on
four binary lines. A “key” is pressed by positioning the tip of the arrow cur-
sor in the desired key number and clicking the mouse button. The binary
data on the output lines will change to reflect the new value and will remain
set until the next key is pressed. The fifth output line will go high momen-
tarily and then low again when a key is pressed.
Hex Display
The hex display shows the hexadecimal equivalent of its four binary inputs.
If any of the inputs is unknown, high impedance, or conflict, an X will be
displayed.
 See Chapter 7, Simulation, for more information on pin delay and
inversion.
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