Mitsubishi Electric RS232/485, MDT652S USER MANUAL

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RS232/485/LAN Serial Communication Control
for MDT652S

1. Application

This document defines the communication protocols for serial control of the MDT652S.

-----Revision History-----

1

st

Release May. 24 2011. H.Tanizoe, M.Juichiya, T.Kimura, Y.Ashizaki

(2/56)

2. Connectors and wiring
A: RS232C connection

Connector: D-Sub 9-pin
Cable: Cross (reversed) cable or null modem cable

B: CAT5 RS485 connection

Connector:

D-SUB 9pin or USB(Either one can be used for communication between PC and CAT5
Tx-BOX and Rx-BOX (Option). In order to use the USB, you need USB driver with your PC
installed. Please check User's manual for details.)
Cable:

(D-SUB 9pin: Full wired Cross (reversed) cable, USB: Standard USB cable (A-B))

Note: The CAT5 serial communication function requires half duplex communication control by DTR and
RTS control which is not required by simple RS232C control. The RS485 communication function is
different fromRS232C control method. Please check Appendix B for more details.

C: LAN connection

Connector: Modular 8pin (RJ45)
Cable:

Modular 8pin (RJ45),

Strait CAT5/6/7 LAN cable

* If you connect one PC and one display without LAN HUB, you use Cross LAN cable.

PC LAN HUB Display #1

Display #2

LAN cable LAN cables

Note: LAN control is converted to RS-232C control in the display.

USB Cable

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3. Communication Parameter

Set each communication parameters to the PC connected with each kind of cable.

A: RS-232C connection

(1) RS-232C direct connection between PC and Display

Interface

RS-232C (

Asynchronous, Full-duplex)

Baud rate

9600bps

Data length

8bits

Parity

None

Stop bit

1 bit

Flow control None

Communication code

ASCII

Communication signals TXD, RXD

B: CAT5 (OPTION) RS-485 connection

(1) USB connection between PC and CAT5 Tx BOX

Interface

RS-232C (

Asynchronous, Half-duplex)

via USB driver

Baud rate

9600bps

Data length

8bits

Parity

None

Stop bit

1 bit

Flow control None

Communication code

ASCII

Communication signals TXD, RXD, RTS

Note: Set the parameters on to USB driver properties. RTS is negative polarity.

(2)

RS-232C connection between PC and CAT5 Tx BOX

Interface

RS-232C (

Asynchronous, Half-duplex)

Baud rate

9600bps

Data length

8bits

Parity

None

Stop bit

1 bit

Flow control None

Communication code

ASCII

Communication signals TXD, RXD, DTR

Note: DTR is negative polarity.

C: LAN connection

(1) LAN connection between PC and Display

Interface

TCP/IP

DHCP client mode

Changeable (default = OFF: not using)

IP address

Changeable (default = 192.168.0.10: depends on model)

Subnet mask

Changeable (default = 255.255.255.0)

Default gateway

Changeable (default = 192.168.0.1: depends on model)

Port

MDT652S:63007/3007(Both of those ports are available. Use
63007 only if you have no support of legacy products.)

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3.1 Communicati on tim i ng

The controller should wait for a packet interval before next command is sent.
The packet interval needs to be longer than 600msec for the MDT652S.

[Important Information]
HOST system shall send next command after receiving a reply command from Monitor, if it is sequential
commands communication. If Host doesn’t wait for monitor’s reply, monitor operation error may happen.

Time-out error handling operation in Controller: Host Controller shall wait the reply from Monitor, after sending command as
mentioned above. The time-out setting in Host Controller shall be more than 30sec after sending command to Monitor. (Using the
maximum command interval “a

MAX

” is most safety.)

Communication disabled period after power on/off: After Monitor Power on, either by AC switch, Remote Controller or
Serial communication command, Monitor goes initialize mode of controller and can not handle the remote control
commands correctly during the mode. So do NOT send any command at least 7 sec. after monitor power on/off. If you make
the code which send any command after POWER ON/OFF command, please put a wait at least 7 sec. after sending the
command.
About the other commands, please wait the each periods of command interval from PC. (See below example.)

[Available Command list at DC power off status]

MDT652S can’t accept and reply any command except for the following commands when it is in DC power off or power
saving.
Power status Read / Read Model name Read / Serial number Read /Power on / Power off

Example of communication timing

a

1

b1

Command #1

Reply #1

Command #2

Reply #2

* Command interval from PC (Wait sending next command for processing in display.)

a > 7sec: When Command #1 is power command “POWER ON”,”POWER OFF”.
a > 5sec: When Command #1 is video input command “INPUT D-SUB”,”INPUT VIDEO”, etc.
a > 1.8sec: When Command #1 is store the adjusted value command “SAVE CURRENT SETTINGS”,
“SAVE CURRENT SETTINGS QUICK”.
a > 6sec: When Command #1 is “AUTO SETUP”.
a > 30sec: When Command #1 is “FACTORY RESET”, “SCREEN RESET”. (This results in a

MAX

)

a > 600msec: When Command #1 is the others.

* Minimum reply time from display (Additional time depends on command processing in display)

b = 10msec (Typ.): On RS-232C connection (The time depends on models as 10 to 20msec.)
b = 140msec (Typ.): On RS-485 connection (The time depends on models as 90 to 140msec.)
b = 30sec (max): When Command #1 is “FACTORY RESET”, “SCREEN RESET”.

* Command internal gap (Don’t make a longer interval gap between characters.)
C < 10msec: Normal communication for time-out error of each character gap.
(Infinit

y

waiting isn’t supported because of

p

r

ocessing freeze.)

PC

Display

b2

a2

Characters of Command #1

c1

0

0

v P

C

R

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4. Communication Format
4-1.Basic command

This command set supports only the basic control of monitor and does NOT support multi monitor control
by daisy chained connection. This command set will be written in the user’s manual of MDT652S.

1) Control command diagram
The command is structured by the address code, func tion code, data code and end code. The length of the command is different for
each function.

2) Control sequence
(1) The command from a computer to the LCD monitor will be sent in 600ms.
(2) The LCD monitor will send a return command 600ms* after it has received and encoded. If the command isn ’t
received correctly, the LCD monitor will not send the return command.
(3) The personal computer checks the command and confirms if the command, which has been sent, has been executed or not.
(4) This LCD monitor sends various codes other than return code. Whe n ha ving a control sequence by RS-232C, reject other
codes from personal computers side.
*: The sending time of return command may delay de pending on the condition (during changing of the input signal, etc.).

Example: Turn the power ON ( ’ ’ is for ASCII code)

Note: The replied status is for communication confirmation. When you want to know the display condition, please use the ‘Read
command’. (See page 6)

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3) Operation commands
The operation commands execute the basic operation setting of this LCD monitor.
It may not operate when changing the signal:

Operation

ASCII

HEX

POWER ON

!

21h

POWER OFF

"

22h

INPUT HDMI

_r1

5Fh 72h 31h

INPUT DVI-D

_r2

5Fh 72h 32h

INPUT D-SUB

_r3

5Fh 72h 33h

INPUT BNC _r4 5Fh 72h 34h

INPUT CAT5 _r5 5Fh 72h 35h

INPUT DisplayPort _r6 5Fh 72h 36h

INPUT VIDEO

_v1

5Fh 76h 31h

INPUT YPbPr

_v2

5Fh 76h 32h

INPUT S-VIDEO*

_v3

5Fh 76h 33h

* S-VIDEO is SEPARATE only

4) Read command
Host computer sends the command without Data-code to monitor.
After receiving this command, the monitor returns the command with Data-code of current status to host comput er.
< ex. > When Host computer ask Power status of monitor, the status of monitor is powered-on.

Structure of the Read-command

ASCII

HEX

Function

Data (Receive)

Function

Data (Receive)

ON

vP

1

76 50

31

POWER

OFF(sleep/stand by) vP

0

76 50

30

HDMI

vI

r1

76 49

72 31

DVI-D

vI

r2

76 49

72 32

D-SUB

vI

r3

76 49

72 33

BNC

vI

r4

76 49

72 34

CAT5 vI

r5

76 49

72 35

DisplayPort vI

r6

76 49

72 36

Video

vI

v1

76 49

76 31

YPｂPr

vI

v2

76 49

76 32

Input

S-VIDEO

vI

v3

76 49

76 33

HIGHBRIGHT

vM

p1

76 4D

70 31

Picture mode

STANDARD

vM

p2

76 4D

70 32

Around
Main
board

resolution
1˚C

tc1

(ex.) +25

74 63 31

2B 20 32 35

Temperature
of Internal
monitor

Around
Power
PCB

resolution
1˚C

tc2

(ex.) +31

74 63 32

2B 20 33 31

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5) Remote command

(Not executable in sleep/stand-by mode. When the remote commands are sent while sleep/stand-by mode, the stand-by mode is

only canceled.)

Some remote control operations can be achieved by the remote command codes. The remote commands have no data c odes.

Function

Button’s name on remote

Character ASCII

+/VOLUME r06 72h 30h 36h

-/VOLUME r07 72h 30h 37h
AV MUTE ra6 72h 61h 36h
AUTO SETUP r09

72h 30h 39h

[Example] When executing the AUTOSETUP. (Figures and symbols enclosed in quotation marks are ASCII codes.):

Sending commands
from the PC, etc.

Status code
from the projector

Description

‘30’ ‘30’ ‘72’ ‘30’ ‘39’ ‘0D’
00r09

Command operating the same
as the MENU button

‘30’ ‘30’ ‘72’ ‘30’ ‘39’ ‘0D’
00r09

Command receipt confirmation
(Command echo back)

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4-2.Extended command

Note: This command set supports multi monitor control by daisy chained connection. This command
set will NOT be written in the user’s manual of MDT652S.

The command packet consists of four parts, Header, Message, Check code and Delimiter.

Sequence of a typical procedure to control a monitor is as follows,

[A controller and a monitor, two-way communication composition figure]

Header Message Check Code Delimiter

Monitor Controller

H

eader

Messa

g

e

Check Code Delimiter

H

eader

Message

Check Code

D

elimiter

Get Parameter

Get Parameter Reply

H

eader

Messa

g

e

Check Code Delimiter

Set Parameter

H

eader

Message

Check Code

D

elimiter

Set Parameter Reply

H

eader

Messa

g

e

Check Code Delimiter

H

eader

Message

Check Code

D

elimiter

Get Parameter Reply

Save Current Setting Comman

d

Get Parameter

H

eader

Messa

g

e

Check Code Delimiter

The controller sends a command to
get a value from the monitor that
you want to change.

The monitor replies with the
current value of the requested
item.

The controller sends commands to
set an adjusted value.

The monitor replies to the
controller for confirmation.

The controller sends a command to
get a value for confirmation.

The monitor replies with an
adjusted value.

The controller requests to store
the adjusted value to the monitor.

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4.1 Header block format (fixed length)

1stbyte) SOH: Start of Header

ASCII SOH (01h)

2

nd

byte) Reserved: Reserved for future extensions.

MDT652S must be ASCII '0'(30h)

3

rd

byte) Destination: Destination equipment ID. (Receiver)

Specify a command’s receiver’s address.

If the command should be sent to certain monitor only, the either of character ‘A’(41h) to ‘Z’(5Ah)
which is corresponding to monitor ID from No1 to No.26 should be set to this portion. If it
is a broad cast command(only “set command” is available), then the ’*’(2Ah)should be applied.

4

th

byte) Source: Source equipment ID. (Sender)

Specify a sender address.
The controller must be ‘0’(30h).

5

th

byte) Message Type: (Case sensitive.)

Refer to section 4.2 “Message block format” for more details.
ASCII 'A' (41h): Command
ASCII 'B' (42h): Command reply.
ASCII 'C' (43h): Get current parameter from a monitor.

ASCII 'D' (44h): "Get parameter" reply.
ASCII 'E' (45h): Set parameter.

ASCII 'F' (46h): "Set parameter" reply.

6

th

-7th bytes) Message Length:
Specify the length of the message (that follows the header) from STX to ETX.
This length includes STX and ETX.
The byte data must be encoded to ASCII characters.
Ex.) The byte data 3Ah must be encoded to ASCII characters '3' and 'A' (33h and 41h).

The byte data 0Bh must be encoded to ASCII characters '0' and 'B' (30h and 42h).

Header

Message Check code Delimiter

SOH

Reserved

'0'

Destination

'A'

Source

Message

Type

Message

Length

1st 2

nd

3

rd

4

th

5

th

6

th

-7th

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4.2 Message block format

“Message block format” is allied to the “Message Type” in the “Header”.
Refer to the section 6 “Message format” for more detail.

1

）

Get current parameter

The controller sends this message when you want to get the status of the monitor.
For the status that you want to get, specify the “OP code page” and “OP code”,
refer to “Appendix A. Operation code table”.

“Message format” of the “Get current parameter” is as follows;



Refer to section 5.1 “Get current parameter from a monitor.” for more details.

2

）

Get Parameter reply
The monitor will reply with the status of the requested item specified by the controller
in the “Get parameter message”.

“Message format” of the “Get parameter reply” is as follows;



Refer to section 5.2 “Get parameter reply” for more details.

3

）

Set parameter

The controller sends this message to change a setting of the monitor.
Message format of the “Set parameter” is as follows;



Refer to section 5.3 “Set parameter” for more details.

4

）

Set Parameter reply

The monitor replies with this message for a confirmation of the “Set parameter message”.
Message format of the “Set parameter reply” is as follows;

Result OP code page OP code Type Max value

Requested setting

Value

ETX

STX

Hi Lo Hi Lo Hi Lo Hi Lo MSB LSB MSB LSB



Refer to section 5.4 “Set parameter reply” for more details.

5

）

Command

“Command message” format depends on each command.
Usually, this “command message” is used for some non-slider controls and some special operations,
such as “Save current settings”, “Get timing report”, “power control”, “Schedule”, etc. Refer to
section 5.5 “Commands message” for more details.

Header

Message

Check code Delimiter

OP code page OP code

STX

Hi Lo Hi Lo

ETX

Result OP code page OP code Type Max value Current Value

STX

Hi Lo Hi Lo Hi Lo Hi Lo MSB LSB MSB LSB

ETX

OP code page OP code Set Value

STX

Hi Lo Hi Lo MSB LSB

ETX

(11/56)

6

）

Command reply

The monitor replies to a query from the controller.
“Command reply message” format depends on each command.
Refer to section 5.5 “Commands message” for more details.

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4.5 Check code

Check code is the Block Check Code (BCC) between the Header and the End of Message except SOH.

D

n+1

= D1 XOR D2 XOR D3 XOR ,,, D

n

XOR: Exclusive OR

Following is an example of a Check code (BCC) calculation.

Check code (BCC) D

17

= D1 xor D2 xor D3 xor … xor D14 xor D15 xor D16
= 30h xor 41h xor 30h xor 45h xor 30h xor 41h
xor 02h xor 30h xor 30h xor 31h xor 30h xor 30h
xor 30h xor 36h xor 34h xor 03h
= 77h

4.6 Delimiter

Packet delimiter code; ASCII CR(0Dh).

Header Message

Check code

Delimiter

2

7

26 25 24 23 22 21 20
SOH D0
Reserved D1
Destination D2
Source D3
Type D4
Length D5
STX D6
Data D7
| |
| |
ETX Dn
Check code D

n+1

P P P P P P P P

Header Message

SOH Reserved

Destination

Address

Source

Address

Message

type

Message length STX

OP code

page

OP code

Set Value ETX

Check

code

(BCC)

Delimiter

01 30 41 30 45 30 41 02 30 30 31 30 30 30 36 34 03 77 0D

D0 D1 D

2

D

3

D

4

D

5

D

6

D7 D8D9D10D11D12D13 D14 D15 D16D

17

D18

Header Message Check code

Delimiter

(13/56)

5. Message type

5.1 Get current Parameter fro m a m onit or.

Send this message when you want to get the status of a monitor.
For the status that you want to get, specify the “OP code page” the “OP code”, refer to “Appendix
A. Operation code table”.

1

st

byte) STX: Start of Message

ASCII STX (02h)

2

nd-3rd

bytes) OP code page: Operation code page.
Specify the “OP code page” for the control which you want to get the status.
Refer to “Appendix A Operation code table” for each item.
OP code page data must be encoded to ASCII characters.
Ex.) The byte data 02h must be encoded to ASCII characters '0' and '2' (30h

and 32h).
OP code page 02h -> OP code page (Hi) = ASCII '0' (30h)
OP code page (Lo) = ASCII '2' (32h)
Refer to Operation code table. (Appendix A)

4

th–5th

bytes) OP code: Operation code
Refer to “Appendix A Operation code table” for each item.
OP code data must be encoded to ASCII characters.
Ex.) The byte data 3Ah must be encoded to ASCII characters '3' and 'A' (33h and 41h).
OP code 3Ah -> OP code (Hi) = ASCII '3' (33h)
OP code (Lo) = ASCII 'A' (41h)
Refer to Operation code table.

6

th

byte) ETX: End of Message

ASCII ETX (03h)

5.2 "Get parameter" reply

MDT652S replies with a current value and the status of the requested item (operation code).

1

st

byte) STX: Start of Message

ASCII STX (02h)

2

nd-3rd

bytes) Result code.

These bytes indicate a result of the requested commands as follows,

OP code page OP code

STX

Hi Lo Hi Lo

ETX

1st 2

nd-3rd

4

th–5th

6

th

Result OP code page OP code Type Max value Current Value

STX

Hi Lo Hi Lo Hi Lo Hi Lo MSB LSB MSB LSB

ETX

1st 2

nd-3rd

4

th–5th

6

th

–7th 8th -9

th

10th -13th 14th -17th 18th

(14/56)

00h: No Error.

01h: Unsupported operation with this monitor or unsupported operation under current condition.
This result code from the monitor is encoded to ASCII characters.
Ex.) The byte data 01h is encoded to ASCII character '0' and '1' (30h and 31h).

4

th–5th

bytes) OP code page: Operation code page.
These bytes indicate a replying item's OP code page.
This returned value from the monitor is encoded to ASCII characters.
Ex.) The byte data 02h is encoded to ASCII character '0' and '2' (30h and 32h).
Refer to the operation codes table.

6

th

–7thbytes) OP code: Operation code

These bytes indicate a replying item's OP code.
This returned value from the monitor is encoded to ASCII characters.
Refer to the operation code table.
Ex.) The byte data 1Ah is encoded to ASCII character '1' and 'A' (31h and 41h).

8

th

-9thbytes) Type: Operation type code
This returned value from the monitor is encoded to ASCII characters.
Ex.) The byte data 01h is encoded to ASCII character '0' and '1' (30h and 31h).

00h: Set parameter
01h: Momentary

Like the AutoSetup function which automatically changes the parameter.

10

th

-13thbytes) Max. value: Maximum value which monitor can accept. (16bits)
This returned value from the monitor is encoded to ASCII characters.
Ex.) '0','1','2' and '3' means 0123h (291)

14

th

-17thbytes) Current Value: (16bits)
This returned value from the monitor is encoded to ASCII characters.
Ex.) '0','1','2' and '3' means 0123h (291)

18

th

byte) ETX: End of Message

ASCII ETX (03h)

5.3 Set parameter

Send this message to change monitor’s adjustment and so on.
The controller requests a monitor to change value.

1

st

byte) STX: Start of Message

ASCII STX (02h)

2

nd-3rd

bytes) OP code page: Operation code page

OP code page OP code Set Value

STX

Hi Lo Hi Lo MSB LSB

ETX

1st 2

nd-3rd

4

th-5th

6

th-9th

10

th

(15/56)

This OP code page data must be encoded to ASCII characters.
Ex) The byte data 02h must be encoded to ASCII '0' and '2' (30h and 32h).
Refer to the Operation code table.

4

th-5th

bytes) OP code: Operation code
This OP code data must be encoded to ASCII characters.
OP code 1Ah -> OP code (Hi) = ASCII '1' (31h)
OP code (Lo) = ASCII 'A' (41h)
Refer to the Operation code table.

6

th-9th

bytes) Set value

: (

16bit)
This data must be encoded to ASCII characters.
Ex.) 0123h -> 1

st

(MSB) = ASCII '0' (30h)

2

nd

= ASCII '1' (31h)

3

rd

= ASCII '2' (32h)

4

th

(LSB) = ASCII '3' (33h)

10

th

byte) ETX: End of Message
ASCII ETX (03h)

5.4 "Set parameter" reply

The Monitor echoes back the parameter and status of the requested operation code.
(If command is sent as “Broadcast” then no reply should be sent back.)
1

st

byte) STX: Start of Message

ASCII STX (02h)

2

nd-3rd

bytes) Result code
ASCII '0''0' (30h, 30h): No Error
ASCII '0''1' (30h, 31h): Unsupported operation with this monitor or unsupported operation under
current condition.

4

th-5th

bytes) OP code page: Echoes back the Operation code page for confirmation.

Reply data from the monitor is encoded to ASCII characters.
Ex.) OP code page 02h -> OP code page = ASCII '0' and '2' (30h and 32h)
Refer to Operation code table.

6

th-7th

bytes) OP code: Echoes back the Operation code for confirmation.

Reply data from the monitor is encoded to ASCII characters.
Ex.) OP code 1Ah -> OP code (Hi) = ASCII '1' (31h)
OP code (Lo) = ASCII 'A' (41h)
Refer to Operation code table

Result OP code page OP code Type Max value

Requested setting

Value

STX

Hi Lo Hi Lo Hi Lo Hi Lo MSB LSB MSB LSB

ETX

1st 2nd-3rd 4

th-5th

6

th-7th

8

th-9th

10th-13th 14th -17th 18

th

(16/56)

8th-9thbytes) Type: Operation type code

ASCII '0''0' (30h, 30h): Set parameter
ASCII '0''1' (30h, 31h): Momentary
Like Auto Setup function, that automatically changes the parameter.

10

th

-13thbytes) Max. value: Maximum value that monitor can accept. (16bits)
Reply data from the monitor is encoded to ASCII characters.
Ex.) '0''1''2''3' means 0123h (291)

14

th

-17thbytes) Requested setting Value: Echoes back the parameter for confirmation. (16bits)
Reply data from the monitor is encoded to ASCII characters.
Ex.) '0''1''2''3' means 0123h (291)

18

th

byte) ETX: End of Message
ASCII ETX (03h)

5.5 Commands

"Command message format" depends on each command

.

Some commands are shown with usage. Refer to

section 7 to 10.

5.5.1 Save Current Settings.

The controller requests for the monitor to store the adjusted value.



Send "OC"(30h, 43h) as Save current settings command.



Complete "Save Current setting" command packet as follows;
(The destination “A” (monitor ID of 1) is only an example. It should be changed according
to the target monitor ID)

ASCII: 01h-30h-41h-30h-41h-30h-34h-02h-30h-43h-03h-CHK-0Dh

SOH-'0'-'A'-'0'-'A'-'0'-'4'-STX-'0'-'C'-ETX-CHK- CR

The monitor replies the packet for confirmation as follows;

SOH-'0'-'0'-'A'-'B'-'0'-'6'-STX-'0'-'0'-'0'-'C'-ETX-CHK- CR

5.5.1a Save Current Settings Quick.

The controller requests for the monitor to store the adjusted value.
This command supports only following items, in order to shorten execute time in monitor inside.

CONTRAST, BRIGHT, Color Temperature, IR Control, Inoformation OSD, H-Position, V-Position, Sharpness,

Black Level, Tint, Color, OSD Turn Off, Off Timer, OSD H-Position, OSD V-Position, Power On Delay,
Gamma Selection, Tiling, Monitor ID, Clock, Clock Phase, Zoom, H-Resolution, V-Resolution.

Command code

STX

'0' 'C'

ETX

Command code

STX

'0' 'D'

ETX

(17/56)



Send "OD"(30h, 44h) as Save current settings quick command.



Complete "Save Current setting" command packet as follows;

ASCII: 01h-30h-41h-30h-41h-30h-34h-02h-30h-44h-03h-CHK-0Dh

SOH-'0'-'A'-'0'-'A'-'0'-'4'-STX-'0'-'D'-ETX-CHK- CR

The monitor replies the packet for confirmation as follows;

SOH-'0'-'0'-'A'-'B'-'0'-'6'-STX-'0'-'0'-'0'-'D'-ETX-CHK- CR

5.5.2 Get Timing Report and Timing reply.

The controller requests the monitor to report the displayed image timing.



Send "07"(30h, 37h) as Get Timing Report command.



Complete "Get Timing Report" command packet as follows;
(The destination “A” (monitor ID of 1) is only an example. It should be changed according
to the target monitor ID)

ASCII: 01h-30h-41h-30h-41h-30h-34h-02h-30h-37h-03h-CHK-0Dh

SOH-'0'-'A'-'0'-'A'-'0'-'4'-STX-'0'-'7'-ETX-CHK- CR

The monitor replies status as the following format;



SS: Timing status byte
Bit 7 = 1: Sync Frequency is out of range.

Bit 6 = 1: Unstable count
Bit 5-2 Reserved (Don't care)
Bit 1 1:Positive Horizontal sync polarity.
0:Negative Horizontal sync polarity.
Bit 0 1:Positive Vertical sync polarity.

0:Negative Vertical sync polarity.



H Freq: Horizontal Frequency in unit 0.01kHz



V Freq: Vertical Frequency in unit 0.01Hz

Ex.) When H Freq is '1''2''A''9' (31h, 32h, 41h, 39h), it means 47.77kHz.

5.5.3 NULL Message

The NULL message returned from the monitor is used in the following cases;



A timeout error has occurred. (The default timeout is 10msec for command internal gap.)



The monitor receives an unsupported message type.



The monitor detects a packet BCC (Block Check Code) error.

Command code

STX

'0' '7'

ETX

Command SS H Freq. V Freq.

STX

'4' 'E' Hi Lo MSB LSB MSB LSB

ETX

Command code

STX

'B' 'E'

ETX