ColdFire V1 Full Chip Simulation Connection
FCS Visualization Utilities
605
Microcontrollers Debugger Manual
IT_Keyboard Component
The 20-key IT_Keyboard shown in Figure 28.26 generates an interruption when a key is
pressed.
Figure 28.26 IT_Keyboard Window
These 20 keys are positioned at the intersection of the five lines, X0 to X4, and the four
columns, Y0 to Y3. The resistor R connected to the positive supply gives a logical level 1
when there is no connection (key not pressed). The activation of a line (or column) gives a
logical level 0, and a key pressed on this line (or column) places the column (or the line)
corresponding on the low level. For example, if you activate line X2, column Y3
decreases from logical level 1 to logical level 0 when the « B » key is pressed.
An interruption is raised when an active key (line or column activated) is pressed.
Figure 28.27 IT_Keyboard Constitution