TABLE 4 - DIAGNOSTIC STATUS REGISTER
BIT
BIT NAME
SYMBOL
DESCRIPTION
7
My Reconfiguration 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.
6
Duplicate ID
DUPID
This bit, if high, indicates that the value in the Duplicate 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 or upon a high level on the TA bit of
the Status Register. 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
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.
1,0 (Reserved)
These bits are undefined.
24
SMSC [ SMSC CORPORATION ]
