Request Status - Pioneer LD-V4400 Level I User Manual

Chapter Four • LD-V4400 Level I & III
In the command line, codes such as <SPACE> or <LF> (line feed) that do not affect
player operation are ignored. The length of the command line is limited to the
buffer size. For the LD-V4400, the length of a command string is limited to 20
characters. The <CR> or <LF> are not included in the buffer size.
When all the commands in a string are completely executed, the player transmits the
"completion" message. (It sends an "R" <CR>.) If an error occurs, an error message
such as E04 <CR> is returned by the player. This indicates the error occurrence,
along with the error code. See Sec. 4.2 Error Messages, page 4-3.
The automatic return of an "R" following command execution is called
Status. Automatic Status is very useful when working with some computer
programs, because it allows the program to know the appropriate time to send the
next command. If this function is not used, the command processing time must be
taken into consideration before the next command is sent. (To set Automatic Status
ON or OFF, see the Level III command for Communication Control on page 4-38.)

4.1.1 Request Status

When an error message is received, it may be necessary to determine the player's
current status in order to continue a program. A variety of conditions can occur
which may cause an error code to be sent. Since actual hardware failure in the
player is a relatively rare event, other conditions may be detected which would
allow a program to recover and continue operation. Even when there is no error,
there are occasions when player status or disc information is useful. In such a
case, the Request Status function can be used.
The user may want to find out the current frame number even if there is no error.
Request Status commands can be useful under these conditions. Fifteen Request
Status commands are available on the LD-V4400. The main Request Status
commands in Level III are as follows:
1) To know the active mode of the player:
2) To know the current frame, time, or chapter number:
NOTE: These and additional Request commands are described in Section 4.7.4 on
page 4-31 through Section 4.7.7 on page 4-47.
The status functions are summarized below:
Status Reporting
4-2
Automatic Status
Auto-Completion Message
Error Indication Message
Request Status
LD-V4400 Level I & III User's Manual
TP 116 v1.1 • 9/93
Automatic
?P
?F, ?T, ?C
Figure 4-B