Communication Parameters

(1)

Communication system

Asynchronous

(2)

Interface

RS-232C

(3)

Baud rate

9600 bps

(4)

Data length

8 bits

(5)

Parity

Odd

(6)

Stop bit

1 bit

(7)

Communication code

Hex

Communication Format

8bit

 

8bit

 

8bit

 

8bit

 

8bit

 

8bit

 

 

 

8bit

 

8bit

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Check

 

Sum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data length

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Command 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UNIT ID 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

UNIT ID 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Command 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Command 1

Together with Command 2, this is a number that distin- guishes the various commands.

For ACK, when bit 2 and bit 3 are both “1”, reception of a supported command or data is indicated. When bit 2 is “0”, reception of an unsupported command or data is in- dicated.

Bit 0 and bit 1 should be set as described below.

bit0

bit1

 

0

0

When multiple screens are selected

0

1

Not used

1

0

At time of set ID selection

1

1

At time of regular use

Unit ID 1 and Unit ID 2

1)Unit ID1: Sets a number corresponding to the various sets ID (1 through 4) when multiple screens are se- lected, and to 1 through 256 at the time of set ID selec- tion. “00H” must be output when the ID is not set.

2)Unit ID2: Makes settings on the occasion of simulta- neously operating all sets connected in cascade at the time of multiple screen mode and at the time of set ID selection.

Selection of all sets: FFH

At time of regular setting: 00H

Command 2

Together with Command 1, this is a number that distin- guishes the various commands.

Check Sum (CKS), Error Processing, and ACK

1)Checks for receive data incorporate both the following checksum and RS-232C (odd) parity.

The checksum comprises the following aspects of one transmitted or received frame: Command 1, Unit 1 and 2, Command 2, data length, and the lower order 8 bits of the total data.

Check Sum Example

9FH

40H

4FH

01H

01H

30H

Command 1

Unit ID

Command 2

Data Length

Data

Check Sum

 

 

 

 

 

 

 

 

 

 

 

 

 

Total 130H

2)Error Processing

(1)When the communications interval is 4 ms or greater, the arrival of a subsequent Command 1 will be recognized. If meaningful data cannot be discerned at this time, that data will not be recog- nized.

(2)When the receive data error, checksum error, and the receive data could not all be taken in, ACK is not returned.

3)Returning an ACK

When command processing exceeds 0.5 seconds fol- lowing command reception, an ACK1 for which bit 3 of Command 1 has been set to “0” (during command processing) is returned every 0.5 seconds until com- mand processing is completed. When command pro- cessing is completed, an ACK2 for which bit 3 of Command 1 has been set to “1” (at the end of com- mand processing) is returned every 0.5 seconds until command processing is completed. Bit 1 of Command 1 is set to 0 ; when the UA2 setting is FFH, it becomes possible to simultaneously operate all sets connected in cascade and as a result, ACK is not returned.

Communications Flow

 

 

Personal computer

Plasma display

PC or other external equipment

 

 

 

 

 

 

 

 

 

Various commands

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ACK

When various commands are sent from a personal com- puter (PC) or other external equipment, the display is al- ways ready to receive them.

Note that resending of the command is recommended when an ACK is not returned from the display within 1.5 seconds.

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NEC 42PD2, 50PD1, 50PD1, 42PD2 user manual Communication Parameters, Communication Format