CXD1804BR Datasheet, PDF (74/103 Pages) Sony Corporation – CD-ROM Decoder

CXD1804BR
2-3. Category 01 Commands
These commands can be executed only in the Disconnect status.
2-3-1. Reselect sequences (40h, 42h, 43h)
Description: These are auto sequence commands which are executed when attempting reconnection with the
initiator after Disconnect.
The Reselect command has the following two levels.
a) After Reselect, operation shifts to the Message In phase and the message is transferred.
1) Reselect and Send Message(s) (40h)
Bus-Free → Arbitration → Reselection → Message In
b) Data transfer (Data In or Data Out phase) is executed after a).
1) Reselect, Send Message(s) and Receive Data (42h)
Bus-Free → Arbitration → Reselection → Message In → Data Out
2) Reselect, Send Message(s) and Send Data (43h)
Bus-Free → Arbitration → Reselection → Message In → Data In
Preparation: A number of operations must be performed before issuing this command.
Common operations:
1) Specify the CXD1804AR operation with the SCCONF0 (60h), SCCONF1 (61h) and
SCCONF2 (62h) registers.
2) Set the SCSI ID of the initiator to be reselected and the CXD1804AR's own SCSI ID in the
SCID register (65h).
3) Set the FIFO to empty status with the Flush FIFO command and then write the message to
be transferred in the Message In phase in the FIFO.
Only when transferring data after executing the Message In phase:
4) The decoder block side must be prepared for transfer in advance using Reselect, Send
Message(s) and Receive/Send Data.
Operation:
Bus-Free → Arbitration → Reselection
If the Reselect command is executed, first the CXD1804AR/SCSI2 core first waits for Bus-Free
and then enter Arbitration. Upon successfully winning the Arbitration, it then shifts to Reselection.
a) When the RSLRTLM (3 to 0) bit of the SCCONF1 register is "00h":
This sequence is repeated until both Arbitration and Reselection are completed successfully.
b) When the RSLRTLM (3 to 0) bit of the SCCONF1 register is greater than "00h":
This sequence is repeated for the number of times set by RSLRTLM. When the number of
times reaches the set number, processing stops, a RSLFAIL interrupt and then a FUNCCMPL
interrupt are generated, and then the command is completed.
When the CXD1804AR acquires the right to use the bus during the Arbitration phase, operation
proceeds to the next step only if reconnection with the initiator is successful in the Reselection
phase.
Message In phase
If reconnection is successful, operation shifts to the Message In phase and the message
prepared beforehand in the FIFO, before issuing the command, is transferred to the initiator. If
the attention condition is established during the transfer, ATNCOND and FUNCCMPL interrupts
are generated and transfer stops at that point. However, the first byte of the message (normally
identify) is always transferred.
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