5–4 RIO Block Transfer
Publication
17476.6 - July 1996
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I/O
Image
Chassis Backplane
RIO Link
= path of the BTW
RIO Block Transfer Theory of Operation - Block Transfer Write (BTW)
The user's control program executes a MOV or COP instruction to the M0 file to initiate a BTW. The SLC processor sends BTW
data (via the chassis backplane) to the scanner's M0 block transfer control and write data file. (Refer to the Block Transfer Buffer
Layout section for details on control information.)
The scanner reads the BTW data and control data from the M0 file. One byte of the scanner's I/O image file is used for
handshake purposes. Note that the SLC user program must never read or write to this image space.
In this example, Logical Rack 3, Logical Group 7, Logical Slot 1 is used.
M1 file
M0 file
The M1 file contains BTW status information. (Refer to the Block Transfer Buffer Layout section for details on status information.)
The RIO scanner transfers BTW information across the RIO link to the adapter.
The adapter transfers the BTW information to the appropriate adapter or intelligent I/O module.
1747 RIO
Scanner
Word
8
Word 9
Word 7
Word 5
Word 6
Word 3
Word 4
Word 1
Word 2
Word 0
Logical
Rack 0
Word 26
Word 27
Word 25
Word 30
Word 28
Word 29
Word 31
Logical
Rack 3
Input Image Output Image
One byte is consumed from the
input and output image file for
handshake" purposes.
Group
0
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 0
Group 1
Word 24
Word 23
Group 0
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 7
Slot 0
Slot 1
The steps below detail a successful Block Transfer Write (BTW):
Adapter or
Intelligent
I/O Module
Slot 0
Slot 1
SLC
Processor
➀
➀
SLC 5/02 processor or later
M
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