5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Datasheet
Table 6.4 - Diagnostic Status Register
BIT
BIT NAME
My Reconfiguration MY-
RECON
SYMBOL
DESCRIPTION
7
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.
6
Duplicate ID
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.
5
4
3
Receive
Activity
RCVACT
TOKEN
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 Seen
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.
Excessive NAK
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.
2
1
Tentative ID
New Next ID
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
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.
NXTID
1,0 (Reserved)
These bits are undefined.
Revision 12-05-06
Page 32
SMSC COM20020I Rev D
DATASHEET
SMSC [ SMSC CORPORATION ]
