Motorola M68HC08 Designer Reference Manual page 22

USB and PS/2 Multimedia Keyboard Interface
USB INITIALIZATION
NO
CONFIGURED ?
40ms TIMER TICK ?
SCAN KEY MATRIX
CONVERT SCAN KEY TO
KEYBOARD REPORT
NEW ENDPOINT 1
NEW ENDPOINT 2
Designer Reference Manual
22
Freescale Semiconductor, Inc.
DEVICE
YES
YES
YES
GHOST KEY?
NO
YES
REPORT ?
YES
REPORT ?
YES
USB IDLE FOR
6 ms ?
Figure 1-11. USB Main Routine
USB and PS/2 Multimedia Keyboard Interface
For More Information On This Product,
Go to: www.freescale.com
YES
EP1 TX BUFFER
EMPTY ?
NO
YES
EP2 TX BUFFER
EMPTY ?
NO
SUSPEND DEVICE
TX EP1 IN REPORT
TX EP2 IN REPORT
NO
KEY PRESSED OR
RESUME FROM
HOST ?
YES
DRM014 — Rev 0
MOTOROLA