COM20022I-3.3V Datasheet, PDF (31/73 Pages) SMSC Corporation – 10 Mbps ARCNET (ANSI 878.1) Controller with 2Kx8 On-Chip RAM

10 Mbps ARCNET (ANSI 878.1) Controller with 2Kx8 On-Chip RAM
Datasheet
BIT BIT NAME
0 Transmitter
Available
SYMBOL
DESCRIPTION
TA
This bit, if high, indicates that the transmitter is available for
transmitting. This bit is set when the last byte of scheduled
packet has been transmitted out, or upon execution of a "Disable
Transmitter" command. The TA bit is cleared by issuing the
"Enable Transmit from Page fnn" command after the node next
receives the token. This bit, when set, will cause an interrupt if
the corresponding bit in the IMR is also set.
Table 6.6 - Diagnostic Status Register
BIT BIT NAME
7 My
Reconfiguration
6 Duplicate ID
5 Receive
Activity
4 Token Seen
3 Excessive NAK
2 Tentative ID
1 New Next ID
0 (Reserved)
SYMBOL
DESCRIPTION
MY-
RECON
This bit, if high, indicates that a past reconfiguration was caused
by this node. It is set when the Lost Token Timer times out, and
should be typically read following an interrupt caused by RECON.
Refer to the Improved Diagnostics section for further detail.
DUPID
This bit, if high, indicates that the value in the Node ID Register
matches both Destination ID characters of the token and a
response to this token has occurred. Trailing zero's are also
verified. A logic "1" on this bit indicates a duplicate Node ID, thus
the user should write a new value into the Node ID Register. This
bit is only useful for duplicate ID detection when the device is off
line, that is, when the transmitter is disabled. When the device is
on line this bit will be set every time the device gets the token.
This bit is reset automatically upon reading the Diagnostic Status
Register. Refer to the Improved Diagnostics section for further
detail.
RCVACT This bit, if high, indicates that data activity (logic "1") was
detected on the RXIN pin of the device. Refer to the Improved
Diagnostics section for further detail.
TOKEN
This bit, if high, indicates that a token has been seen on the
network, sent by a node other than this one. Refer to the
Improved Diagnostic section for further detail.
EXCNAK
This bit, if high, indicates that either 128 or 4 Negative
Acknowledgements have occurred in response to the Free Buffer
Enquiry. This bit is cleared upon the "POR Clear Flags"
command. Reading the Diagnostic Status Register does not
clear this bit. This bit, when set, will cause an interrupt if the
corresponding bit in the IMR is also set. Refer to the Improved
Diagnostics section for further detail.
TENTID
This bit, if high, indicates that a response to a token whose DID
matches the value in the Tentative ID Register has occurred.
The second DID and the trailing zero's are not checked. Since
each node sees every token passed around the network, this
feature can be used with the device on-line in order to build and
update a network map. Refer to the Improved Diagnostics
section for further detail.
NEW
NXTID
This bit, if high, indicates that the Next ID Register has been
updated and that a node has either joined or left the network.
Reading the Diagnostic Status Register does not clear this bit.
This bit, when set, will cause an interrupt if the corresponding bit
in the IMR is also set. The bit is cleared by reading the Next ID
Register.
This bit is undefined.
SMSC COM20022I 3.3V Rev.C
Page 31
DATASHEET
Revision 03-08-07