Return to previous page ｜ Return to menu ｜ Go to next page

3.3 Response

(1) Response content

The response consists of a 1-byte status and a 7-byte report. The status is common, but the report depends on the command. The most basic report is a CD report.

(2) Status

The following information is returned in the
status. 
 ・ REJECT (illegal) 
: The command itself is invalid. 
 ・ WAIT (execution pending) 
: The command cannot be accepted because it cannot be executed in the current state. 
 / Data transfer request 
: Indicates that data transfer is required. 
 ・ Periodic response 
: Indicates whether it is a periodic response or a response to a command. 
 / CD drive status 
: Indicates the logical status of the CD drive as seen from the host.

(A) The response at REJECT is invalid.
(B) Drive status and CD report during WAIT are valid, but other reports are invalid.

(3) Periodic response

The periodic response is a response that the CD block returns at the timing of communication with the CD drive, and the host can obtain information (status and CD report) without issuing a command.
∙ Updated regularly with the communication cycle with the CD drive. (SCDQ flag update timing is the same)

* Standard playback speed: 13.3ms
Periodic response update period ・ Double-speed playback: 6.7ms
. .., except during playback: 16.7ms

* The periodic response is not updated during command / response. After reading the response by the command, it will be updated and available at the next CD drive communication timing. 

  Note: The periodic response (SCDQ flag) update cycle shown here is a normal value. With CD drive
The update cycle may be extended depending on the communication status.
(For example, when communication with the CD drive fails due to disc damage, etc.)

Return to previous page ｜ Return to menu ｜ Go to next page