CY7B923
CY7B933
negative at the end of the 6-bit sub-block if the 6-bit
sub-block is 111000, and it is negative at the end of the 4-bit
sub-block if the 4-bit sub-block is 1100.
Table 1. Valid Transmission Characters
Data
DIN or QOUT
3. Otherwise, running disparity at the end of the sub-block is
the same as at the beginning of the sub-block.
Byte Name
765
43210
Hex Value
Use of the Tables for Generating Transmission Characters
D0.0
000
00000
00
The appropriate entry in the table shall be found for the Valid
Data byte or the Special Character byte for which a Trans-
mission Character is to be generated (encoded). The current
value of the Transmitter’s running disparity shall be used to
select the Transmission Character from its corresponding
column. For each Transmission Character transmitted, a new
value of the running disparity shall be calculated. This new
value shall be used as the Transmitter’s current running
disparity for the next Valid Data byte or Special Character byte
to be encoded and transmitted. Table 1 shows naming
notations and examples of valid transmission characters.
D1.0
D2.0
000
000
00001
00010
01
02
.
.
.
.
.
.
.
.
D5.2
010
000101
45
.
.
.
.
.
.
.
.
D30.7
D31.7
111
111
11110
11111
FE
FF
Use of the Tables for Checking the Validity of Received
Transmission Characters
The column corresponding to the current value of the
Receiver’s running disparity shall be searched for the received
Transmission Character. If the received Transmission
Character is found in the proper column, then the Trans-
mission Character is valid and the associated Data byte or
Special Character code is determined (decoded). If the
received Transmission Character is not found in that column,
then the Transmission Character is invalid. This is called a
code violation. Independent of the Transmission Character’s
validity, the received Transmission Character shall be used to
calculate a new value of running disparity. The new value shall
be used as the Receiver’s current running disparity for the next
received Transmission Character.
Detection of a code violation does not necessarily show that
the Transmission Character in which the code violation was
detected is in error. Code violations may result from a prior
error that altered the running disparity of the bit stream which
did not result in a detectable error at the Transmission
Character in which the error occurred. Table 2 shows an
example of this behavior.
Table 2. Code Violations Resulting from Prior Errors
RD
–
Character
D21.1
RD
–
Character
D10.2
RD
–
Character
D23.5
RD
+
Transmitted data character
Transmitted bit stream
Bit stream after error
–
101010 1001
101010 1011
D21.0
–
010101 0101
010101 0101
D10.2
–
111010 1010
111010 1010
Code Violation
+
–
+
+
+
Decoded data character
–
+
+
+
Document #: 38-02017 Rev. *E
Page 16 of 33
CYPRESS [ CYPRESS ]
