Rockwell Automation 6008-SV2R VMEbus remote I/O Scanner - Manual (Page 168)

Chapter
Programming the Scanner
8
8Ć34
Here is a brief review of the protocol to issue a block-transfer command:
1. Test and set the scanner’s semaphore.
2. Place the command code and other required data in the scanner’s
control/status and general data area.
3. Interrupt the scanner to let it know it should process your command.
The scanner puts the block-transfer request in its queue and sends a
confirmation status code. The scanner then interrupts the VME
master processor.
4. The application program should acknowledge the interrupt and clear
the semaphore.
Upon issuing a block-transfer request, the scanner writes 0x2F in the
confirmation status byte to indicate that the scanner accepted the request
and put it into its queue. When the scanner actually completes the
block-transfer, the scanner sets the semaphore and then it updates this data
in the following order:
1. address
2. block transfer tag
3. length of data
4. confirmation status
5. block transfer read data
6. command complete interrupt (if enabled)
The scanner executes block-transfers in run and test modes. In program
mode, the scanner only queues block-transfers.
The programming example on page 8-13 shows how to program a single
block-transfer command in the scanner. These following examples show
how to update block-transfer data and how to test for complete
block-transfer operations.
Programming
Block Transfers