UR5HCFJL Datasheet, PDF(6/20 Page) Semtech Corporation – Zero-PowerTM Keyboard Encoder for Portable Systems

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UR5HCFJL Datasheet, PDF (6/20 Pages) Semtech Corporation – Zero-PowerTM Keyboard Encoder for Portable Systems

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PC COMMUNICATION

The UR5HCFJL implements all the

standard functions of

communication with a BIOS-

compatible PC/XT or AT/PS/2 host

system. Two lines, KC and KD,

provide bi-directional clock and

data signals. In addition, the

UR5HCFJL supports all commands

from and to the system, as

described in the IBM Technical

Reference Manuals.

The following table shows the

commands that the system may

send and their values in hex.

Command

Hex Value

Set/Reset Status

Indicators

Echo

Invalid Command

Select Alternate

Scan Codes

Invalid Command

Read ID

Set Typematic

Rate/Delay

Enable

Default Disable

Set Default

Set All Keys

Typematic

Make/Break

Make

Typematic/Make/Break

Set Key Type

Typematic

Make/Break

Make

Resend

Reset

Table 2: Keyboard Commands from the

System (AT/PS/2 protocol)

These commands are supported in

the AT/PS/2 protocol and can be

sent to the keyboard at any time.

The following table shows the

commands that the keyboard may

send to the system.

Command

Hex Value

Key Detection

00*

Error/Overrun

Keyboard ID

83AB

BAT Completion Code

BAT Failure Code

Echo

Acknowledge (Ack)

Resend

Key Detection

Error/Overrun

FF**

*Code Sets 2 and 3

**Code Set 1

Table 3: Keyboard Commands to the

System (AT/PS/2 protocol)

When an external keyboard is

connected, commands from the

system will also be directed to the

external keyboard. Presence or

absence of an external device will

not effect the normal operation of

the GreenCoderTM.

DOC5-FJL-DS-106

www.semtech.com

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