S_RESET or setting the STOP
bit.
This bit is always read/write ac-
cessible. COLE 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.
BCR5: LED1 Status
BCR5 controls the function(s) that the LED1 pin dis-
plays. Multiple functions can be simultaneously en-
abled on this LED pin. The LED display will indicate the
logical OR of the enabled functions. BCR5 defaults to
Receive Status (RCV) with pulse stretcher enabled
(PSE = 1) and is fully programmable.
This bit is always read/write ac-
cessible. RCVME is cleared by
H_RESET and is not affected by
S_RESET or setting the STOP
bit.
Note: When LEDPE (BCR2, bit 12) is set to 1, pro-
gramming of the LED1 Status register is enabled.
When LEDPE is cleared to 0, programming of the
LED1 register is disabled. Writes to those registers will
be ignored.
Note: Bits 15-0 in this register are programmable
through the EEPROM.
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.
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
This bit is always read/write ac-
cessible. XMTE is cleared by
H_RESET and is not affected by
S_RESET or setting the STOP
bit.
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.
3
2
POWER
RCVE
Power. When this bit is set to 1,
the device is operating in HIGH
power mode.
The logical value of the LEDOUT
status signal is determined by the
settings of the individual Status
Enable bits of the LED register
(bits 8 and 6-0).
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.
This bit is always read accessi-
ble. This bit is read only; writes
have no effect. LEDOUT is unaf-
fected by H_RESET, S_RESET,
or STOP.
This bit is always read/write ac-
cessible. RCVE is cleared by
H_RESET and is not affected by
S_RESET or setting the STOP
bit.
14
LEDPOL
LED Polarity. When this bit has
the value 0, then the LED pin will
be driven to a LOW level whenev-
er the OR of the enabled signals
is true, and the LED pin will be
disabled and allowed to float high
whenever the OR of the enabled
signals is false (i.e., the LED out-
put will be an Open Drain output
and the output value will be the
inverse of the LEDOUT status
bit).
1
0
SPEED
COLE
Speed. When this bit is set to 1,
the device is operating in HIGH
speed mode.
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.
Am79C978
149
AMD [ AMD ]
