Motorola M68HC08 Designer Reference Manual page 9

DRM014 — Rev 0
MOTOROLA
Freescale Semiconductor, Inc.
Figure 1-1 shows the block diagram of the keyboard. The solution
includes the JB8, key button inputs and LED indicator outputs only. The
connections of the corresponding USB and PS/2 signals are shown in
Figure 1-2. The USB to PS/2 converter standard connections are the
USB D– and D+ pins connected to the PS/2 Data and Clock pins
respectively.
Figure 1-3 shows the printed circuit board and
schematic of the keyboard.
• J1 is used for USB connection
• J2 is used for PS/2 mouse connection (for future development)
• J3 and J7 are used for in-circuit programming
• 8 rows x 18 columns key matrix is implemented
– 8 rows implemented in PTA[7:0]
– 18 columns implemented in PTB[7:0], PTC[7:0], PTE0 and
PTE2
• Keyboard LEDs
– Scroll Lock at PTD2
– Caps Lock at PTD3
– Num Lock at PTD4
Figure 1-4 shows the key matrix for the 107 standard keyboard with
power management keys (Power, Wake and Sleep).
the key matrix for multimedia keyboard with function key.
USB and PS/2 Multimedia Keyboard Interface
For More Information On This Product,
Go to: www.freescale.com
USB and PS/2 Multimedia Keyboard Interface
Hardware Descriptions
Figure 1-16
Figure 1-5
Designer Reference Manual
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