Command Block Format; Communication Protocol; Starting Up The Monitor - Sony HR Trinitron PVM-20M7MDE Interface Manual For Programmers

Communication via the RS-232C Interface

Command Block Format

Data is sent between the computer and the monitor in
the following format.
STX Byte Destination
count address address
1 byte 1 byte 1 byte
STX
Start of text code value: 02H (the suffix "H" indicates
a hexadecimal (16) number)
Byte Count
This indicates the number of data bytes (maximum 255
bytes) which have been inserted between this byte and
the checksum byte.
Values 00H, 01H and 02H are illegal values.
Destination address
One byte address value which defines where data
composed of the above format is transmitted to. Value
02H should be specified when the command is sent
from the computer to the monitor.
Source address
One byte address which defines where the data was
sent from. This defines where the response
corresponding to commands sent will be returned
from. Values from 41H to 7FH should be specified.
when the command is sent from the computer to the
monitor.
Command block
This designates a particular command.
For detailed information, see "Command Description" on
page 6.
Checksum
This value is set to make the lower eight bits of the
sum of all bytes from the Byte Count to the Checksum
inclusive zero.

Communication Protocol

The computer takes the initiative in communication
between the computer and the monitor.
When the monitor receives a command from the
4
Source Command block Checksum
1 byte n bytes
computer, it sends back the following responses
corresponding to the commands sent from the
computer within 9 milliseconds of receiving the
commands.
• NAK (05H)
When the received command is an undefined
command or a communication error occurs.
• Specific Code + DATA
When the received command is a question requiring
1 byte
a reply.
• ACK
When the received command is anything other than
the above two.
The remote control should not issue any other
commands until the response has been received from
the monitor.
The remote control should not leave a gap between
bytes to be transmitted of more than ten milliseconds.
Otherwise the monitor will treat the message as
received in error.
If the remote control unit receives a NAK from the
monitor it must wait more than ten milliseconds before
transmitting any more messages.

Starting Up the Monitor

To start up the monitor, proceed as follows.
1
Connect the serial cable to the RS-232C connector
on the back of the monitor and connect the other
end to the computer.
2
Turn on the power on the monitor.
3
Turn on the power on the computer.
4
Set the serial parameters for the computer's RS-
232C interface.
The monitor can then be controlled from the computer.
It can also be controlled from the operation panel of
the monitor. The monitor is factory-set to LOCAL
mode. In this mode, the monitor cannot be controlled
from the computer. You should set the monitor to
REMOTE (FRONT LOCK) or REMOTE & LOCAL
mode to control the monitor from the computer using
the monitor's on-screen menu.
For detailed information on how to select REMOTE or
REMOTE & LOCAL mode, refer to the instruction manual
supplied with the monitor.