COM20020_00 Datasheet, PDF (33/82 Pages) SMSC Corporation – Universal Local Area Network Controller with 2K x 8 On-Board RAM

Table 4 - Status Register
BIT BIT NAME
7 Receiver
Inhibited
6,5 (Reserved)
4 Power On Reset
3 Test
2 Reconfiguration
1 Transmitter
Message
Acknowledged
SYMBOL
DESCRIPTION
RI
This bit, if high, indicates that the receiver is not enabled because
either an "Enable Receive to Page fnn" command was never
issued, or a packet has been deposited into the RAM buffer page
fnn as specified by the last "Enable Receive to Page fnn"
command. No messages will be received until this command is
issued, and once the message has been received, the RI bit is set,
thereby inhibiting the receiver. The RI bit is cleared by issuing an
"Enable Receive to Page fnn" command. This bit, when set, will
cause an interrupt if the corresponding bit of the Interrupt Mask
Register (IMR) is also set. When this bit is set and another station
attempts to send a packet to this station, this station will send a
NAK.
These bits are undefined.
POR
This bit, if high, indicates that the COM20020 has been reset by
either a software reset, a hardware reset, or writing 00H to the
Node ID Register. The POR bit is cleared by the "Clear Flags"
command.
TEST
This bit is intended for test and diagnostic purposes. It is a logic
"0" under normal operating conditions.
RECON
This bit, if high, indicates that the Line Idle Timer has timed out
because the RXIN pin was idle for 41μS. The RECON bit is
cleared during a "Clear Flags" command. This bit, when set, will
cause an interrupt if the corresponding bit in the IMR is also set.
The interrupt service routine should consist of examining the
MYRECON bit of the Diagnostic Status Register to determine
whether there are consecutive reconfigurations caused by this
node.
TMA
This bit, if high, indicates that the packet transmitted as a result of
an "Enable Transmit from Page fnn" command has been
acknowledged. This bit should only be considered valid after the
TA bit (bit 0) is set. Broadcast messages are never acknowledged.
The TMA bit is cleared by issuing the "Enable Transmit from Page
fnn" command.
33
DISCONTINUED DATASHEET