Hi G Tek IGRS46D916, IGRS40916 Users Manual

Chapter 6

RS 485/232

Communication

Protocol

6

RS 485/232 Communication Protocol

6.1. RS- 485/232 Communication Protocol:
General Description

Communication between the Local Site Controller LSC and the
STAR READER is based on the master/slave approach. The LSC
is the MASTER unit, the READERS are the SLAVE units.
The LSC and the READERS communicate via a RS-485 multi
drop or RS-232 connection. Each READER has its own address,
enabling the LSC to approach each reader individually.

6.2. Physical Layer

6.2.1. Down-link

Down-link is the link from the LSC to the READERS. The link is
RS-485 or RS-232 half duplex. Data rate can be one of the
following: 2400, 4800, 9600, 19200, 38400 BPS. The default rate
is set at 9600 BPS.

6.2.2. Up-link

Up-link is the link from the READERS to the LSC. The link is
RS-485 or RS-232 half duplex. Data rate can be one of the
following: 2400, 4800, 9600, 19200, 38400 BPS. The default rate
is set at 9600 BPS.

6.3. Protocol Flow.

Communication is initiated by a command sent by the LSC to the
READER. The READER executes the command and responds
accordingly. In a long command session, the session is concluded
when the LSC acknowledges the READER within T = 50 msec.

ACK

If the READERS are in sleep mode, the LSC must ensure they are
awakened prior to the initialization of the session. In this case, the
LSC should wait T = 50 msec before sending the main command.

w

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

116

6

RS 485/232 Communication Protocol

There are 2 types of commands: SHORT COMMANDS and LONG
COMMANDS.

Short Commands: These are commands that are relevant to

internal tasks at the reader level.
Long Commands: These commands involve sessions with seals.

The READER will respond to commands generated by the LSC
within T seconds.

For short commands, response time should be: T = 50 msec.

RLSC

RLSC

For long commands, the LSC should return to retrieve the results
after T with the appropriate GET RESULTS command.

T is a derivative of the type of command executed to the seals.

session

session

Acknowledge can be positive or negative.
If the LSC detects a problem, Acknowledge will be negative.

The READERS are designed to work in cycles. Following an
internal or external trigger, a READER SESSION is generated.
This is a full communication cycle going back and forth between
a READER and the tags located in the READER's receiving zone.

The LSC operates differently The READERs are scanned on a
different time line, using the same frequency as that of the
READER's cycles or greater.

This protocol supports RS-485 and RS-232 communication
fashions. When working with the LSC using RS-232 communication
opposite only one device, address fields should be set to 0xFFFF.
When using RS-485 communication in broadcast situations, the
address field should be set to 0x0000.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

117

6

Short Commands Mode:

Long Commands Mode:

RS 485/232 Communication Protocol

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

118

6

STX #B R# CMND data CRC ETX

1 2 2 2 n 2 1

# of bytes

#B

RS 485/232 Communication Protocol

6.4. String Formats.

6.4.1. LSC to READERS messages.

Commands & Acknowledge strings:

CRC

Where:

STX This is the marker for the beginning of the
messages. STX = 02 hex.
#B String length, the string contains the R#,CMND,
the DATA field, and the CRC.
R# This session's READER address .
CMND This session's command code .
DATA The data field contains the data required to execute
the command
CRC This is the cyclic redundancy check for DATA and
fields #B, R#, CMND.
ETX This is the marker for the end of the messages.
ETX = 03 hex.

6.4.1.1. CRC Calculation.

CRC calculations are based on the following CCITT polynomial:

The result is 2 bytes.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

X + X + X + 1

16 12 5

119

6

6.4.1.2. CMND Field Structure.

The command field is divided into several sections:

Where:

DIR Denotes string direction. In case of a command
from the LSC to the reader, it is equal to 0.
PK Denotes whether the command transmitted is
composed of packets or not. PK = 0 is for non-packet
commands. PK = 1 is for packet commands.
ERR this flag indicates an error.
ERR = 0 no error.
ERR = 1 Error. The first byte in the data field is the
error code.
CT Is the scenario command type. It describes the

CC

RS 485/232 Communication Protocol

command type, and whether it is in short or long form

00000 designates SHORT commands that stream
from the LCR to the Reader for MCU purposes.
00011 is for LONG commands.
This is the command code .

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

120

6

6.4.2. Reader to LSC Message

Response & Acknowledge strings:

RS 485/232 Communication Protocol

STX

#B

R#

MSGT

MC
R_status

DATA
CRC

ETX

This is the marker for the beginning of the messages.
STX=02 hex.
String length, the string contains the R#, MSGT, MC,
R_status, the DATA field and the CRC.
This is the address of the READER for the current
session.
This is the message type response for the current
session. The MSGT corresponds to a specific
command (see paragraph 6.4.2.1)
This is the message code (see paragraph 5.2)
This is the status field of the reader. The field contains
bytes A&B (see paragraph 6.4.2.2)

The data field contains the relevant response data.
This is the cyclic redundancy check for fields #B,
MSGT, R_status and DATA.
This is the marker for the end of the messages.
ETX=03 hex.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

121

6

6.4.2.1. MSGT Field Structure.

The Message Type field is divided into several sections:

Where:

RS 485/232 Communication Protocol

DIR
PK

ERR

MT

MC

Is the string direction.Response will be 1.
Denotes whether the transmitted message is

composed of packets. A response of 1 indicates
that the message is composed of packets. If the
response is 0, the message was transmitted without
packets. (If PK=0 there must be 1 reserved data byte).

This flag indicates an error.
ERR = 0 no error.
ERR = 1 Error. The first byte in the data field stores
the error code.

This code reflects the nature of the response. A
regular response to a command has the same value
as the CC (See paragraph 6.4.1.2).

This field holds the same value as the Command
Code of the related commands. This field makes it
possible to link the response to the appropriate
command.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

122

6

Byte A Byte B Byte C Byte D

7 6 5 4 3 2 1 0

LCK 485 PCR PER VCCERR VBERR PMC EDC

RS 485/232 Communication Protocol

6.4.2.2. R_Status Field Structure

The READER's STATUS field is 4 bytes.

Byte A represents the status of the main motherboard MCU.
The other bytes represent the RF modems' status.
In a general Reader response the R-Status reply contains
bytes A&B only.
In a GET Status command, the reply contains all the R-Status
bytes.

Byte A:

Where:
LCK

If the response shows 0, the READER's parameters
are locked.
If the response is 1, the READER's parameters
are unlocked.
If the response is 0, the READER is using RS-232
mode for communication.

485

If the response shows 1, the READER is using
RS-485 mode for communication.

PCR

If the response shows 0, the parameters in the MCU's

2

E ROM are OK.
If the reponse is 1, parameters were corrupted and
successfully restored.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

123

6

7 6 5 4 3 2 1 0

Ch1 Ch2 Ch3 Ch4 Ch1err Ch2err Ch3err Ch4err

RS 485/232 Communication Protocol

PER

VCCERR

VBERR

PMC

EDC

Byte B:

Where:

If the response is 0, the parameters in the
MCU's E ROM are OK.

2

If the answer is 1, parameters are corrupted.

If response is 0, internal power is OK.
If response is 1, internal power is faulty.

If response shows 0, internal battery is OK.
If response is1, internal battery is faulty.

If response is 0, program memory in the MCU is OK.
If response is 1, program memory is corrupted.

This flag indicates that a delayed command was
triggered and is in process.

Ch1

if 0 channel1 is not in use.
If 1 channel1 is in use.

Ch2

Iif 0 channel2 is not in use.
If 1 channel2 is in use.

Ch3

If 0 channel3 is not in use.
If 1 channel3 is in use.

Ch4

If 0 channel4 is not in use.
If 1 channel4 is in use.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

124

6

RS 485/232 Communication Protocol

Ch1err

Ch2err

Ch3err

Ch4err

Bytes C&D:

If 0, channel is OK
If 1, channel is defective, details are in byte C. If
byte C flags are OK, there is a communication
failure with this channel.I
If 0, channe2 is OK.
If 1, channe2 is defective, details are in byte C.
If byte C flags are OK, there is a communication
failure with this channel.
If 0, channe3 is OK.
If 1, channe3 is defective, details are in byte D. If
byte D flags are OK, there is a communication
failure with this channel.
If 0, channe4 is OK.
If 1, channe4 is defective, details are in byte D.
If byte D flags are OK, there is a communication
failure with this channel.

VCCERR

If 0, power is OK.
If 1, power is not faulty

PMC

EMC

EME

If 0, program memory in the module is OK.
If 1, program memory is corrupted.
If 0, E ROM is OK.
If 1, E ROM was corrupted and then restored.
If 0, E ROM is OK.
If 1, E ROM was corrupted.

2

2

2

2

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

125

6

6.4.2.3. Reader Messages Packed Data Format

Where:

RS 485/232 Communication Protocol

PK

P#
Ch

Maximum total message length is 128 bytes.
Maximum Data* length is 115 bytes.

6.4.2.3.1. Packed Data from the LSC.
When the packets originate with the LSC, each packet will be

transmitted after an appropriate response from the READER.
The LSC may retransmit the last packet upon receipt of a
response indicating that the last packet was not received
satisfactorily.

6.4.2.3.2. Packed Data from the READER.

When the packets originate with the READER, each packet will be
transmitted after an appropriate acknowledgement from the LSC.
The READER may retransmit the last packet upon receipt of an
acknowledgment indicating that the packet was not received
satisfactorily

The first byte is the total number of packets in
the string.
The second byte is the packet serial number.
The third byte is the channel number from which
the message is received.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

126

6

# Commands

Set

Command
Code

Comments

1

Wakeup E0 h This command wakens REA DERS it hat were in sl eep

mode.

2

Execute RF
cmnd

20 h This comm and generates an appropriat e command from

the READE R to the tags .

3

Get Results 15 h In a tag-reader sess ion, thi s com mand allows t he LSC to

retrieve the results received by the REA DER from the tags.
.

4

Get Status 16 h In case of a sel f-contained c ommand, t he READER will

return to it s current s tatus .

5

Get Burs t
Mess age

1C h This comm and should be us ed to retrieve the alert

mess ages retrieved from the seal s when using t he alert
burst mode. These are not available through the regular Get
Results .

6

Reset
Reader

14 h This comm and resets theREADER.

7

Write
Parameters

06 h This comm and modifies the PARAM ETERS of a READER.

After is suing a LOCK c ommand, not all the paramet ers are
accessible.

8

Read
Parameters

07 h This comm and is to read the PARAM ETERS of a READE R.

9

BIT 09 h Exec utes a built in t est

10

Sleep 08 h This comm and puts t he READER int o the sleep mode of

operation to enabl e power conservation.

11

Unsync Ack 0A h Reserved for the unsynchroniz ed response, see table 5. 2

12

Get Reader’s
baud rate

FF h This comm and allows t he LSC to obtain t he reader’s baud

rate.

13

Set Reader
baud rate

FE h This comm and allows t he LSC to s et the REA DER’s baud

rate.

14

Set Reader’s
Address

12 h This comm and sets the READE R’s address for RS-485

usage

15

Ack nowledge
OK

92 h This is an ac knowledgement of a mes sage com ing from a

READER.

16

Ack nowledge
Failed

94 h This is an ac knowledgement of an improper mess age

coming from a RE ADER.

17

Save
Command

0F h This comm and saves one of the above commands for lat er

execut ion. It is used to synchroniz e readers.

18

Exec ute
Saved
command

17 h This comm and executes the c ommand saved in the

READER. When is used in a broadcas t fashion, all the
READERS execut e the command sim ultaneousl y.

19

Read
Channel
Definitions

11 h This comm and allows the reading of channel definitions ..

20

Write
Channel
Definitions

10 h This comm and allows the writing of channel defini tions.

RS 485/232 Communication Protocol

6.5. LSC and Reader Messages.

6.5.1. LSC Commands and Acknowledge Table:

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

127

6

#

Message Message

Code

Commen ts

1

Wak eup
response

- No response for W AKE UP st ring

2

Exec ute RF
cmnd res ponse

20 h

3

Get Results
response

15 h

4

Get Status
response

16 h

5

Get Burs t
Mess age
response

1C h

6

Reset Reader
response

14 h

7

Write
Parameters
response

06 h

8

Read
Parameters
response

07 h

9

BIT response 09 h

10

Sleep response 08 h

11

Unsynch
Mess age

0A h When a REA DER is i n unsync h mode, the RE ADER

may s end an unsync h mess age. This oc curs after
receiving an alert mes sage from a seal .

12

Get Reader’s
baud rate
response

FF h

13

Set Reader
baud rate
response

FE h

14

Set Reader’s
Address
response

12 h

15

Save
Command
response

0F h This comm and saves one of the above commands for

later exec ution. It is us ed to sy nchroniz e readers.

16

Exec ute Saved
command
response

_ This is a broadc ast c ommand. There is noresponse t o

this command.

17

Read Channel
Definitions
response

11 h This command allows t he reading of channel

definitions .

18

Writ e Channel
Definitions
response

10 h This command allows t he writing of channel definitions ..

RS 485/232 Communication Protocol

6.5.2. Message Table:

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

128

6

# Parameter

Name

Parameter
Code

Parameter
Syntax

Read/Write
Access *

Default
value
[unit]

Unit Parameter

length

1

Version of
MCU_firmwar
e

01 h MVER R 2 Byte

2

Version of
S1_firmware

80 h SVER1 R 2 Byte

3

Version of
S2_firmware

40 h SVER2 R 2 Byte

4

RSSI ch1 87 h RSSI1 R 1 Byte

5

RSSI ch2 47 h RSSI2 R 1 Byte

6

Reader ID 02 h RID R / 1 00000000 4 Byte

7

ADI ch1 81 h ADI1 R/W 00000000 4 Byte

8

ADI ch2 41 h ADI2 R/W 00000000 4 Byte

9

OrgID* 04 h OrgID R / 2 0000 2 Byte

10

Department
ch1

82 h DEP1 R/W 1 Byte

11

Department
ch2

42 h DEP2 R/W 1 Byte

12

Thw ch1 85 h Thw1 R/W 997 3.072ms 2 Byte

13

Thw ch2 45 h Thw2 R/W 997 3.072ms 2 Byte

14

Reader
Address

03 h RADD R/W 0000 2 Byte

15

Transmitter
Power ch1

88 h TRPOR1 R/W 65 1 Byte

16

Transmitter
Power ch2

48 h TRPOR2 R/W 65 1 Byte

17

System ch1 83 h SYS1 R/W ** 1 Byte

18

System ch2 43 h SYS2 R/W ** 1 Byte

19

Mode ch1 84 h MODE1 R/W 00 1 Byte

20

Mode ch2 44 h MODE2 R/W 00 1 Byte

21

Hard wakeup
ch1

86 h T

HP1

R/W 3256 3.072ms 2 Byte

22

Hard wakeup
ch2

46 h T

HP1

R/W 3256 3.072ms 2 Byte

RS 485/232 Communication Protocol

6.5.3. Parameters Table:

The following table relates to the Read and Write Parameters
Commands:

* /1 or /2 defines the LOCK level.

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

129

6

Parameters Format:

6.5.3.1. Reader Master Firmware Version MVER,

MVER is the version of the master firmware. This is a read only
parameter.

Bits assignment:

6.5.3.2. Reader Slave1 Firmware Version SVER1.

SVER1 is the version of the first slave's firmware.
This is a read only parameter.

Bits assignment:

RS 485/232 Communication Protocol

6.5.3.3. Reader Slave1 Firmware Version SVER2,

SVER2 is the version of the second slave's firmware.
This is a read only parameter.

Bits assignment:

Hi-G-Tek Ltd. Microelectronics & Asset Tracking Technology

130