Function of Control/Status Bits
Chapter 6
617
When transferring multiple strings, the module will not split a string
between two block transfers, and the string length cannot exceed the
number of characters that can be transferred in 31 words. Two strings of
31 words, three strings of 20 words, and so forth, must total 62 words or
less. Remember that two of the 64 block transfer words are reserved for
status words. Do not confuse the transfer of multiple strings per block
with the transfer of one long string between two or more block transfers.
The module will split one long string between block transfers when you
have selected single string transfer, IW2(17)=0.
Command word one, status word one, and status word two are
summarized in Figure 5.2, Figure 5.3, and Figure 5.4, respectively.
Command, initialization and status words are summarized in the tables on
the following pages. Copy the figures and tables so that you can refer to
them as needed.
Figure 5.2
Command Word One, CW1
17
16
15
14
13
12
11
10
07
06
05
04
03
02
01
00
Initia
liza
tion
Write
Data
Avail
able
Read
Data
Ack
now
ledge
Send
In
com
plete
String
Port
Dis
able
Self
Diag
nos
tics
0
Reset
Power
up and
Hand
shak
ing Bit
0
Reset
Input
Buffer
Full
Bit
0
0
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