CS89712
3.18.13 Line Status Register (LineST, address offset 134h)
7
6
LinkOK
C
B
PolarityOK
5:0
010100
A
LineST reports the status of the Ethernet physical interface.
F
9
10BT
E
CRS
8
RSVD
Bit
5:0
7
8
9
C
E
Description
010100: These bits provide an internal address used by the CS89712 to identify this as register
14, the Line Status Register. When reading this register, these bits will be 010100, where the
LSB corresponds to Bit 0.
LinkOK: If set, the 10BASE-T link has not failed. When clear, the link has failed, either
because the CS89712 has just come out of reset, or because the receiver has not detected
any activity (link pulses or received packets) for at least 50 ms.
RSVD: Reserved; must be a “0” when writing to this register.
10BT: If set, the CS89712 is using the 10BASE-T interface.
PolarityOK: If set, the polarity of the 10BASE-T receive signal (at the RXD+ / RXD- inputs) is
correct. If clear, the polarity is reversed. If PolarityDis (Register 13, LineCTL, Bit C) is clear, the
polarity is automatically corrected, if needed. The PolarityOK status bit shows the true state of
the incoming polarity independent of the PolarityDis control bit. Thus, if PolarityDis is clear and
PolarityOK is clear, then the receive polarity is inverted, and corrected.
CRS: This bit tells the software the status of an incoming frame. If CRS is set, a frame is cur-
rently being received. CRS remains asserted until the end of frame (EOF). At EOF, CRS goes
inactive in about 1.3 to 2.3 bit times after the last low-to-high transition of the recovered data.
Table 78. Line Status
Reset value is: 0000 0000 0001 0100
128
DS502PP2