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10.9.2
Data Address and Module
Address
10.9.3
File Address
10.9.4
Block Length
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The module address is stored in BCD in the data address of the read and
write instructions. In this example, the module address is 130: rack 1,
module group 3, slot 0.
Two data addresses must be used. In this example, they are 040 and 041.
Both contain the module address. For bidirectional operation, each data
address word also contains an enable bit; bit 16 for a write operation (in
041) and bit 17 for a read operation (in 040). When the processor searches
the data addresses in the timer/counter accumulated area of the data table,
it finds two consecutive data addresses both containing the same module
address. The read bit is set high in one data address (040). The write bit
is set high in the other (041). When the processor finds a match of the
module address and the enable bit (read or write bit) for the desired
direction of transfer, it then locates the file address to which (or from
which) the data will be transferred.
Generally two file addresses are required: one to receive data transferred
from the module, the other containing data to be transferred to the module.
In this example, they are 060 and 070. The consecutive storage locations
containing the file addresses in BCD are found in the preset area of the
data table at addresses 140 and 141. They are found 100
corresponding consecutive data addresses in the accumulated area of the
data table.
The block lengths of the read and write instructions can be set equal
or unequal to each other up to any value not exceeding the default
(maximum) block length of the module. If the default value is used, it
instructs the module to control the number of words transferred. Although
the default value varies from one kind of module to another, it can be
entered into the instruction block as the number 00 for all block transfer
modules. See the module data sheet for additional information on the block
transfer module of interest.
In the example, both block lengths are set equal to 05.
Chapter 10
Block Transfer
above the
8
10 17
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