1747-6.22, Backup Scanner User Manual

SLC
Processor
➀
RIO Block Transfer Theory of Operation-Block Transfer Read (BTR)
Chassis Backplane
M0 file
M1 file
_ _ _ = path of the BTR
1 SLC 5/02 processor or later
1.
RIO Block Transfer 7-105
In this example, Logical Rack 0, Logical Group 0, Logical Slot 1 is used.
M
Files
1747 RIO
Scanner
I/O
Image
RIO Link
Adapter or
Intelligent I/O
Module
Logical
Rack 0
Logical
Rack 3
One byte is consumed from the input
and output images file for "handshake"
purposes.
Group 0
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7
Group 0
Group 1
Group 7 Word 23
Group 0 Word 24
Group 1 Word 25
Group 2 Word 26
Group 3 Word 27
Group 4 Word 28
Group 5 Word 29
Group 6 Word 30
Group 7 Word 31
Input Image Output Image
Word 0
Word 1
Word 2
Word 3
Word 4
Word 5
Word 6
Word 7
Word 8
Word 9
Slot 1
Slot 0
Slot 1
Slot 0
The steps below detail a successful Block Transfer Read (BTR):
1. The MO file contains BTR control information which controls
(initiates) the scanner BTR operation. (Refer to the Block
Transfer Buffer Layout section for details on control
information.)
2. The SLC control program initiates a block transfer read by
commanding the scanner to perform the read operation. The
adapter/intelligent I/O module sends BTR data across the RIO
link to the RIO scanner.
3. The scanner writes the BTR data to a unique M1 file location
that you specify. Also, one byte of the scanner’s I.O image file is
used for "handshake" purposes between the scanner and the
adapter/intelligent I/O module. Note that the SLC control
program must never read of write to this "handshake" image
space.
4. Using the M1 file and a COP instruction in the control program
the scanner transfers the BTR data to the SLC processor via the
chassis backplane. The M1 file also contains BTR status
information. (Refer to the Block Transfer Buffer Layout section
for details on status information.)
5. The SLC control program processes the BTR information.
Publication 1747-6.22