UR5HCSPI View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'UR5HCSPI' PDF : 20 Pages View PDF
COMMUNICATION PROTOCOL
There are eight commands that may be sent from the UR5HCSPI to the host, and ten commands that may be sent
from the host to the UR5HCSPI.
Each command from UR5HCSPI to the host is composed of a sequence of codes. All commands start with
<CONTROL> code (80H) and end with LRC code (see the description of the LRC calculation on page 12).
Command details are listed below.
Commands to the Host - Summary
Command Name
Code
Initialize Request
AOH
Initialize Complete
A1H
Heartbeat Response
A2H
Identification Response
F2H
LED Status Report
A3H
Resend Request
A5H
Description
Sent to the host when the data buffer is full
Issued upon completion of the “Initialize” command issued by the host
Response to “Heartbeat Request” issued by the host
Response to “Identification Request” issued by the host
Response to “LED Status Request”
Issued upon error during the reception of a packet
LRC CALCULATION
The LRC is calculated for the
whole packet, including the
Command Code and the
Command Prefix. 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.
COMMANDS TO THE HOST ANALYTICALLY
Initialize Request
<CONTROL>
80H
<INIT>
A0H
<LRC>
20H
The UR5HCSPI will send the Initialize Request Command to the host when
its data buffer is full.
Initialization Complete
<CONTROL>
80H
<INIT COMPLETE>
A1H
<LRC>
21H
The UR5HCSPI wil send the Initialize Complete Report to the host when it
finishes the initialization caused by Initialize Command from the host.
Heartbeat Response
<CONTROL>
80H
<ONLINE>
A2H
<LRC>
22H
The UR5HCSPI will send the Heartbeat Response to the host when it
receives the Heartbeat Request Command from the host.
Identification Response
<CONTROL>
80H
<ID>
F2H
<Vendor>
02H
--- USAR
<Revision>
08H
--- Rev 0.8A
<Switch>
00H
.
<LRC>
7EH
The UR5HCSPI will send the Identification Response to the host when it
receives the Identification Request Command from the host.
Copyright Semtech 1997-2001
11
DOC5-SPI-DS-117
www.semtech.com
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