Motorola MC68838 User Manual page 76

Media access controller
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TOKEN_SEND—Type of Token To Send after This Frame Is Sent
If this frame is the last frame sent after receipt of a token, this field indicates the type of
token that should be sent (i.e., restricted token, unrestricted token, the token type
received, or no token).
00 = No token is released.
01 = An unrestricted token is released.
10 = A restricted token is released.
11 = Whatever token type was originally captured is the type sent (i.e., use R_FLAG).
If this is not the last frame sent with this captured token, this bit field has no
effect. This bit field can be used in immediate mode to create a token.
EXTRA_FS—Send Extra Frame Status Indicators
This MAC chip allows an extra two FS indicators to be sent. This chip will always send
the first three FS indicators as R-symbols. There is no way to send less than three or to
send S-symbols instead of R-symbols for these first three indicators.
x00 = TR RR II
001 = TR RR RR ll
101 = TR RR SR ll
010 = TR RR RS ll
110 = TR RR SS II
011 = TR RR RT ll
111 = TR RR ST ll
8-6
ll
x = don't care.
MC68838 USER'S MANUAL
MOTOROLA

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