Évaluations - 3, GPA: 4.3
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Multiple parameter sets cannot be included within the same packet. 38 19.2 One-way Protocol Communication Flow A session starts with the receiving device sending a request using a BDR, or with the sending device sending BDS data. The session ends after transfer of all the data in the parameter set being transferred by the sending device is complete. Data is divided into multiple packets of 256 bytes or less each, and transfers them at fixed intervals (20 msec). A final EOD informs the receiving device when the session is ended. Data Receiver Data Sender Operation BDR > Send Request (Optional) < BDS Data Transfer (20 msec or greater interval) < BDS Data Transfer (20 msec or greater interval) < BDS Data Transfer (20 msec or greater interval) : : < EOD Data End 19.3 Handshake Protocol Communication Flow A session starts with the receiving device sending a request using an HDR or with the sending device sending HDS data. The sending device does not send the next packet until it receives an ACK from the receiving device. The maximum wait time of at least 2000 msec is reserved. Failure of a response to arrive within the wait time (at least 2000 msec) is treated as a timeout error, and data communication is terminated. The sending device resends the last data if the receiving device returns an HDE (error) due to checksum mismatch, incompatible data structure, or some other reason. If an error repeats a number of times (undefined), either the sending device or the receiving device sends an HDJ to terminate the session. A session ends after the sending device sends all the parameter sets, and sends a final EOD in response to an HAD (ACK) from the sending device. Data Receiver Data Sender Operation HDR > Send Request (Optional) < HDS Data Send HDA > Acknowledge < HDS Data Send HDA > Acknowledge : : HDA > Acknowledge < EOD Data End The same packet is resent when a checksum mismatch or incompatible data structure error is detected. 39 Data Receiver Data Sender Operation HDR > Send Request (Optional) < HDS Data Send HDA > Acknowledge < HDS Data Send HDE > Error < HDS Data Resend : : HDE > Error < EOD Data End Data send is canceled when no acknowledgement (ACK) is received. Data Receiver Data Sender Operation HDR > Send Request (Optional) < HDS Data Send HDA > Acknowledge < HDS Data Send HDJ > Rejection (Send Canceled) The session can be canceled for any reason by sending an HDJ. The HDJ can be sent by the sending device or the receiving device. The bulk dump session is terminated immediately upon receipt of an HDJ. Data Receiver Data Sender Operation HDR > Send Request (Optional) < HDS Data Send HDA > Acknowledge < HDS Data Send : : HDJ > Data Receive Rejected (Send Canceled) Data Receiver Data Sender Operation HDR > Send Request (Optional) HDA > Acknowledge < HDS Data Send HDA > Acknowledge < HDS Data Send : : < HDJ Data Send Rejected (Send Canceled) 40 In the case of the WK-3500, for example, when a communication request is received from an external source while floppy disk control is being performed, BSY is returned to an external device that sends BDS, BDR, HDS, HDR. When the BSY is received, the receiver must wait until this Model enters a session-enabled mode, or use a Prepare for Data Management parameter (see "20.2 Data Management Command List") to change to a communication-enabled mode. Data Receiver Data Sender Operation BDR > < BSY (Send Canceled) Send Request Busy Data Receiver BDS > < Data Sender BSY (Send Canceled) Operation Data Send Busy Data Receiver HDR > < Data Sender BSY (Send Canceled) Operation Send Request Busy Data Receiver Data Sender Operation HDS > Data Send < BSY Busy (Send Canceled) The same packet is resent when a checksum mismatch or incompatible data structure error is detected. 41 Part V Parameter Lists These lists show the parameters that can be transferred individually using System Exclusive Messages. • Note 1: Any parameter that has "r" to the right of its Parameter ID number is a read-only parameter that can be used for obtaining status information only. A parameter with "w" next to its Parameter ID is a write-only parameter, which is used for commands, etc. • Note 2: All values in the System Exclusive Format table are hexadecimal. Except for the "Setting Value" column, all values in the Parameter Lists are hexadecimal, unless specifically noted otherwise. • Note 3: Receipt of a value outside a specified range causes the value marked "Default" to be used instead. 20 Command Parameters The parameters defined here mainly execute commands and indicate statuses. Values indicate the pointer to a command or a status. 20.1 System Parameter List System Exclusive Format Field Value 01 SYSEX F0 02 MAN 44 03 MOD 11,02 04 dev Either 00 to 1F, or 7F 05 act 00(IPC), 01(IPR) 06 cat Command = 0 07 prm 00-7F 08 ilen/dlen 0 / bit size - 1 09 ps LSB,MSB = 00, 00 10 index 00 11 data See the Parameter List 12 sum None 13 EOX F7 42 System Parameter List ParamID Parameter ps index bit Value Default Setting...