CD2231

Manufacturer Part NumberCD2231
DescriptionCD2231 Intelligent Two-channel Lan And Wan Communications Controller
ManufacturerIntel Corporation
CD2231 datasheet
 


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
Page 71
72
Page 72
73
Page 73
74
Page 74
75
Page 75
76
Page 76
77
Page 77
78
Page 78
79
Page 79
80
Page 80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
Page 75/178

Download datasheet (3Mb)Embed
PrevNext
Intelligent Two-Channel LAN and WAN Communications Controller — CD2231
Figure 18. ARAP 2.0 Frame
Start Flag
SOH
ESC
STX
data
NOTE: The DLE (ARAP 1.0) and ESC (ARAP 2.0) characters in the middle of the data stream, indicated by the
‘T’ column, are inserted for transparency and thus not included in the FCS calculation.
6.5
Async Processing
Data is transmitted according to the format options defined in the Channel Option registers. These
options determine the character length, parity, and Stop bit length. New data sent from the host is
transmitted in a continuous stream, unless one of the following occurs:
Transmitter disabled — transmission terminated at the end of the current character until
transmitter enabled.
XOFF received from line — transmission terminated at end of the current character until XON
received or transmitter enabled.
Out-of-band flow control — transmission terminated at the end of the current character until
out-of-band flow control removed.
In-line command received in data stream from host — in-line command is executed and
transmission resumed.
Send special character command from host — the current character is completed and the
special character is transmitted after which normal transmission is resumed.
6.5.1
Transmitter In-Band Flow Control
For in-band flow control modes to be active, the Special Character Detect mode must be enabled.
Transmit in-band flow control is enabled when the TxIBE (Transmit In-Band Enable) bit
(COR2[6]) is set to ‘1’. When TxIBE is set to ‘0’, in-band flow control is disabled, the IXM
(Implied XON Mode) bit, also in COR2[7], has no meaning. The XON and XOFF characters are
defined in the Special Character registers SCHR[1] and SCHR[2].
When in-band flow control is enabled (TxIBE = 1), and an XOFF character is received, the channel
stops transmission after the current character in the Transmit Shift register and the current
character in the Transmit Holding register are transmitted. When IXM = 0, transmission restarts
after an XON character is received. When IXM = 1, transmission restarts after any character is
received.
The FCT (flow control transparency) Mode bit (COR3[5]) determines whether to pass the received
flow control characters to the host. If FCT = 1, the characters are not passed to the host. If FCT = 0,
they are passed to the host as exception characters. This bit does not affect non-flow control special
characters.
Additional status information about transmitter in-band flow control is available in the CSR
(Channel Status register). The TxFloff (Transmit Flow Off) and TxFlon (Transmit Flow On) bits
CSR[2:1] are used.
Datasheet
T
data
DLE
DLE
data
End Flag
data
ESC
ETX
FCS1
FCS2
75