Sony 70P Car Stereo System User Manual


 
8
DSR Series
5. Communication Protocol
1) All communication between the CONTROLLER and the DEVICE will be under the direct supervi-
sion of the CONTROLLER.
When the DEVICE receives the COMMAND sent from CONTROLLER, the following COMMAND
is returned.
. In the case that the DEVICE receives the COMMAND not required the data
..................... ACK
. In the case that the DEVICE receives the COMMAND required the data
..................... COMMAND + DATA
. In the case that the error communication is detected or the undefined COMMAND is received
..................... NAK + ERROR DATA
2) The CONTROLLER is not transmit additional COMMAND blocks to a DEVICE prior to receivers
an appropriate response to a previous COMMAND block.
3) The CONTROLLER is not interrupt transmission of a byte in a COMMAND block for more than 10
ms. A DEVICE detecting an interruption of a byte in a COMMAND block that exceeds 10 ms.
CONTROLLER execute a TIME-OUT error sequence.
A DEVICE will void the receiving COMMAND block and transmit a NAK (TIME OUT).
4) The DEVICE, following receipt of a COMMAND block from the CONTROLLER will transmit a
response within 9 ms.
Therefore if the CONTROLLER cannot receive the appropriate response from the DEVICE within
10 ms. After performing the COMMAND block transmission, it will execute as the communication
is not performed under the normal condition, and it will process as necessary.
5) The DEVICE, upon detection of an error, it will immediately transmit a NAK to the CONTROLLER.
(The contents of an error is shown on the COMMAND tables.)
The CONTROLLER, upon receipt of NAK, it will immediately stop transmission of the COM-
MAND block. The DEVICE, following transmission of NAK, it will receive a subsequent COM-
MAND block within 10 ms. (except NAK UNDEFINED COMMAND) and will process as neces-
sary.