EKK8011E ELAN Microelectronics Corp, EKK8011E Datasheet - Page 10

• Manufacturer Part Number: EKK8011E
• Description: Usb And Ps/2 Keyboard Encoder
• Manufacturer: ELAN Microelectronics Corp

eKK8011E
USB & PS/2 Keyboard Encoder
6 •
The keyboard checks the clock line status at least every 5 milliseconds. If a system
Request to Send (RTS) is detected, the keyboard clocks 11 bits in. After the 10th bit,
the keyboard checks for a high state in the data line then pulls it low and clocks one
more bit to signal the system that data has been received. If data is low after the 10th
bit, it indicates a frame error. The keyboard should continue to count until the data line
goes high, then pulls it low and issues a Resend to the system.
6.1.5 Command from the System
The system can send commands to the keyboard at any time. The keyboard needs to
respond within 20 milliseconds, unless the system prevents keyboard output, when
doing self test or executing a reset. The following are the keyboard input commands
and actions that the keyboard needs to take.
Set/Reset Status indicators (Hex ED)
Echo (Hex EEH)
Invalid commands (Hex EF and F1)
Select Alternate Scan Codes (Hex F0)
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Respond with EE hex
Return to previous scanning state
Return a RESEND command
Return to previous scanning state
Respond with ACK
Clear output buffer
Set the default Typematic rate/delay
Clear last Typematic key
Receive option byte
Respond with ACK
Option byte : 01 : Select Scan Code Set 1
Return to previous scanning rate
Respond with ACK
Receive option byte
Respond with ACK
Update status indicators
Return to previous scanning state
02 : Select Scan Code Set 2
03 : Select Scan Code Set 3
(This specification is subject to change without further notice)
Product Specification (V1.2) 07.09.2009