UR8HC007-001 Datasheet, PDF (8/18 Pages) Semtech Corporation – Input Device and Power Management Companion IC for Jupiter Devices

PROTOCOLS, COMMANDS AND REPORTS, (CON’T)
HID Data Report
General Commands Format
The Pointing Device Data Reports
format covers both absolute (where
applicable) and relative positioning
devices. In addition, it provides
support for MouseWheel-type of
input devices.
Keyboard Data Report
The Keyboard Data Reports return
changes on the keyboard matrix or
the External PS/2 keyboard device.
Keys are uniquely identified
according to the Key Number table
listed in Appendix A of the Juno^TM
Technical Reference Manual. The
Key Up or Key Release numbers
comprise the logic OR of the Key
Number and 80H.
LRC (Longitudinal
Redundancy Check)
The LRC is calculated for the
whole packet, including the
Protocol Header. The LRC is
calculated by first taking the
bitwise exclusive OR of all bytes
from the message. If the most
significant bit (MSB) of the LRC is
set, the LRC is modified by
clearing the MSB and changing the
state of the next most significant
bit. Thus, the Packet Check Byte
will never consist of a valid LRC
with the most significant bit set.
For protocols used by either the host or the UR8HC007, a set of simple
commands is implemented. These support the basic communication
protocol and handle reset and errors in transmission.
A simple command would have the following structure:
Header (80H)
Command Code
LRC
Simple Command Structure
Following is a summary of the simple commands used by both the Host
and the UR8HC007:
Simple Commands Summary
Command
Initialize
Protocol
Simple
Initialization Complete Simple
Resend Request
Simple
Cmd Code
20H
21H
25H
Description
Forces the recipient to enter the
known default power-on state
Issued as a hand-shake response
only to the "Initialize" command.
Issued upon error in the reception
of a package. The recipient will
resend the last transmitted packet
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