CY7B923
CY7B933
Valid Special Character Codes and Sequences (SC/D = HIGH)[1, 2]
Bits
EDCBA
Current RD−
abcdei fghj
001111 0100
Current RD+
S.C. Byte Name
K28.0
S.C. Code Name
HGF
000
abcdei
fghj
1011
C0.0
(C00)
(C01)
(C02)
(C03)
(C04)
(C05)
(C06)
(C07)
(C08)
(C09)
(C0A)
(C0B)
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
110000
110000
110000
110000
110000
110000
110000
110000
000101
001001
010001
100001
K28.1
C1.0
C2.0
C3.0
C4.0
C5.0
C6.0
C7.0
C8.0
C9.0
C10.0
C11.0
000
000
000
000
000
000
000
000
000
000
000
001111
001111
001111
001111
001111
001111
001111
111010
110110
101110
011110
1001
0101
0011
0010
1010
0110
1000
1000
1000
1000
1000
0110
1010
1100
1101
0101
1001
0111
0111
0111
0111
0111
K28.2
K28.3
K28.4
K28.5
K28.6
K28.7
K23.7
K27.7
K29.7
K30.7
Idle
C0.1
C1.1
(C20)
(C21)
001
001
00000
00001
−K28.5+,D21.4,D21.5,D21.5,repeat[3]
−K28.5+,D21.4,D10.2,D10.2,repeat[4]
R_RDY
EOFxx
C−SOF
P−SOF
C2.1
(C22)
001
00010
−K28.5,Dn.xxx0[5]+K28.5,Dn.xxx1[5]
Follows K28.1 for ESCON Connect−SOF (Rx indication only)
C7.1 (C27) 001 00111 001111
1000
110000
0111
0111
Follows K28.5 for ESCON Passive−SOF (Rx indication only)
C7.2
(C47)
010
00111
001111
1000
110000
Code Rule Violation and SVS Tx Pattern
Exception
−K28.5
C0.7
C1.7
C2.7
(CE0)
(CE1)
(CE2)
111
111
111
00000
00001
00010
100111
001111
110000
1000[6]
1010[29]
0101[30]
011000
001111
110000
0111[6]
1010[29]
0101[30]
+K28.5
Running Disparity Violation Pattern
110111 001000
0101[31]
Exception
C4.7
(CE4)
111
00100
1010[31]
Notes:
1. All codes not shown are reserved.
2. Notation for Special Character Byte Name is consistent with Fibre Channel and ESCON naming conventions. Special Character Code Name is intended to
describe binary information present on I/O pins. Common usage for the name can either be in the form used for describing Data patterns (i.e., C0.0 through
C31.7), or in hex notation (i.e., Cnn where nn = the specified value between 00 and FF).
3. C0.1 = Transmit Negative K28.5 (−K28.5+) disregarding Current RD when input is held for only one byte time. If held longer, transmitter begins sending the
repeating transmit sequence −K28.5+, D21.4, D21.5, D21.5, (repeat all four bytes)... defined in X3.230 as the primitive signal “Idle word.” This Special Character
input must be held for four (4) byte times or multiples of four bytes or it will be truncated by the new data. The receiver will never output this Special Character,
since K28.5 is decoded as C5.0, C1.7, or C2.7, and the subsequent bytes are decoded as data.
4. C1.1 = Transmit Negative K28.5 (−K28.5+) disregarding Current RD when input is held for only one byte time. If held longer, transmitter begins sending the
repeating transmit sequence −K28.5+, D21.4, D10.2, D10.2,(repeat all four bytes)... defined in X3.230 as the primitive signal “Receiver_Ready (R_RDY).” This
Special Character input must be held for four (4) byte times or multiples of four bytes or it will be truncated by the new data.
The receiver will never output this Special Character, since K28.5 is decoded as C5.0, C1.7, or C2.7 and the subsequent bytes are decoded as data.
5. C2.1 = Transmit either −K28.5+ or +K28.5− as determined by Current RD and modify the Transmission Character that follows, by setting its least significant bit
to 1 or 0. If Current RD at the start of the following character is plus (+) the LSB is set to 0, and if Current RD is minus (−) the LSB becomes 1. This modification
allows construction of X3.230 “EOF” frame delimiters wherein the second data byte is determined by the Current RD.
For example, to send “EOFdt” the controller could issue the sequence C2.1−D21.4− D21.4−D21.4, and the HOTLink Transmitter will send either
K28.5−D21.4−D21.4−D21.4 or K28.5−D21.5− D21.4−D21.4 based on Current RD. Likewise to send “EOFdti” the controller could issue the sequence
C2.1−D10.4−D21.4−D21.4, and the HOTLink Transmitter will send either K28.5−D10.4−D21.4− D21.4 or K28.5−D10.5−D21.4− D21.4 based on Current RD.
The receiver will never output this Special Character, since K28.5 is decoded as C5.0, C1.7, or C2.7, and the subsequent bytes are decoded as data.
6. C0.7 = Transmit a deliberate code rule violation. The code chosen for this function follows the normal Running Disparity rules. Transmission of this Special
Character has the same effect as asserting SVS = HIGH.
The receiver will only output this Special Character if the Transmission Character being decoded is not found in the tables.
Document #: 38-02017 Rev. *E
Page 25 of 33
CYPRESS [ CYPRESS ]
