Am79C973/Am79C975
169
P R E L I M I N A R Y
Am79C975 controller is function-
ing in a Link Pass state and full-
duplex operation is enabled.
When
the
Am79C975 controller is not func-
tioning in a Link Pass state with
full-duplex operation being en-
abled, a value of 0 is passed to
the LEDOUT signal.
Am79C973/
Read/Write accessible always.
FDLSE is cleared by H_RESET
and is not affected by S_RESET
or setting the STOP bit.
7
PSE
Pulse Stretcher Enable. When
this bit is set, the LED illumination
time is extended for each new oc-
currence of the enabled function
for this LED output. A value of 0
disables the pulse stretcher.
Read/Write accessible always.
PSE is set to 1 by H_RESET and
is not affected by S_RESET or
setting the STOP bit.
6
LNKSE
Link Status Enable. When this bit
is set, a value of 1 will be passed
to the LEDOUT bit in this register
in Link Pass state.
Read/Write accessible always.
LNKSE is cleared by H_RESET
and is not affected by S_RESET
or setting the STOP bit.
5
RCVME
Receive Match Status Enable.
When this bit is set, a value of 1 is
passed to the LEDOUT bit in this
register when there is receive ac-
tivity on the network that has
passed the address match func-
tion for this node. All address
matching modes are included:
physical, logical filtering, broad-
cast, and promiscuous.
Read/Write accessible always.
RCVME is cleared by H_RESET
and is not affected by S_RESET
or setting the STOP bit.
4
XMTE
Transmit Status Enable. When
this bit is set, a value of 1 is
passed to the LEDOUT bit in this
register when there is transmit
activity on the network.
Read/Write accessible always.
XMTE is cleared by H_RESET
and is not affected by S_RESET
or setting the STOP bit.
3
RES
Reserved location. Written and
read as zeros.
2
RCVE
Receive Status Enable. When
this bit is set, a value of 1 is
passed to the LEDOUT bit in this
register when there is receive ac-
tivity on the network.
Read/Write accessible always.
RCVE is set to 1 by H_RESET
and is not affected by S_RESET
or setting the STOP bit.
1
RES
Reserved location. Written and
read as zeros.
0
COLE
Collision Status Enable. When
this bit is set, a value of 1 is
passed to the LEDOUT bit in this
register when there is collision
activity on the network.
Read/Write accessible always.
COLE is cleared by H_RESET
and is not affected by S_RESET
or setting the STOP bit.
BCR7: LED3 Status
BCR7 controls the function(s) that the LED3 pin dis-
plays. Multiple functions can be simultaneously enabled
on this LED pin. The LED display will indicate the logical
OR of the enabled functions. BCR7 defaults to Transmit
Status (XMT) with pulse stretcher enabled (PSE = 1)
and is fully programmable.
Note:
When LEDPE (BCR2, bit 12) is set to 1, pro-
gramming of the LED3 Status register is enabled.
When LEDPE is cleared to 0, programming of the
LED3 register is disabled. Writes to those registers will
be ignored.
Note:
Bits 15-0 in this register are programmable
through the EEPROM.
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15
LEDOUT
This bit indicates the current
(non-stretched) value of the LED
output pin. A value of 1 in this bit
indicates that the OR of the en-
abled signals is true.