Motorola M68HC08 Designer Reference Manual page 15

PS/2 INITIALIZATION
SEND SELF TEST PASS SEND SELF TEST PASS
HANDLE COMMAND
40ms TIMER TICK ?
SCAN KEY MATRIX
NO
YES
SEND MAKE CODES
FOR KEYS PRESSED
SEND BREAK CODES
FOR KEYS RELEASED
DRM014 — Rev 0
MOTOROLA
Freescale Semiconductor, Inc.
NO
SELF
TEST PASS ?
YES
CODE ($AA) CODE ($AA)
NO
VALID COMMAND
FROM HOST ?
YES
ACK AND
YES
KEYS PRESSED
OR RELEASED
YES
GHOST KEY ?
NO
Figure 1-8. PS/2 Main Routine
USB and PS/2 Multimedia Keyboard Interface
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USB and PS/2 Multimedia Keyboard Interface
SEND SELF TEST SEND SELF TEST
FAIL CODE ($FC) FAIL CODE ($FC)
Designer Reference Manual
Firmware Description
STOP
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