AMD
P R E L I M I N A R Y
Delimiter may be used for start of frame recognition by appropriate
settings of the SD[1:0] bits in the Network Configuration Register
(TCR0). Start of Frame detection is performed on the bits in the or-
der that they appear on the medium, with the SDLT LSB, bit 0, being
checked against the first bit to arrive at the Am79C930 (RX case) or
the first bit to leave the Am79C930 (Tx case) and continuing in
that order.
TCR11: Interrupt Register 3
This register is the TAI Interrupt Register 3. Provides in-
terrupt status information. Any interrupt bit may be
cleared by writing a 1 to the bit location. Writing a 0 to a
bit location has no effect on the bit value. An interrupt in
TCR11 will be signaled in TIR4 through the MOREINT
bit when the associated unmask bit has been set in
TCR12.
CONFIGURATION REGISTER INDEX:
0Bh
Bit
Name
Reset Value
Description
7:4
3
Reserved
U1INT
–
0
Reserved. Must be written as a 0. Reads of these bits produce
undefined data.
USER1 Interrupt. When U1INT is set to 1, it indicates that a change
of state has occurred at the USER1/IRQ12 pin. The change of state
required to signal an interrupt on the U1INT bit is determined by the
settings of the U1INTSC bits of TCR7[4:3]. This function may be
disabled with an appropriate setting of the U1INTSC bits. A corre-
sponding unmask bit for this interrupt source exists in TCR12.
2
RUNERR
1
Run Length Error. When RUNERR is set to a 1, it indicates that the
total number of 1s during a received message exceeds the total
number of 0s at any given time by 25, or that the total number of 0s
in the message at any given time exceeds the number of 1s in the
message by 27. This function may be disabled with the DISRNR bit
of TCR27.
1
0
ATFO
ATFU
0
0
Asynchronous Transmit FIFO Overflow. When ATFO is set to 1, it
indicates that the asynchronous transmit FIFO has overflowed.
Asynchronous Transmit FIFO Underflow. When ATFU is set to 1, it
indicates that the asynchronous transmit FIFO has underflowed.
TCR12: Interrupt Unmask Register 3
This register is the Interrupt Unmask Register 3.
Each bit in this register will unmask the corresponding
interrupt of the Interrupt Register 2 (TIR5) when the un-
mask bit is set to 1.
CONFIGURATION REGISTER INDEX:
0Ch
Bit
Name
Reset Value
Description
7:4
Reserved
–
Reserved. Must be written as a 0. Reads of these bits produce
undefined data.
3
2
1
0
U1INTU
RUNERRU
ATFOU
0
0
0
0
USER1 Interrupt Unmask.
RUNERR Interrupt Unmask.
Asynchronous Transmit FIFO Overflow Interrupt Unmask.
Asynchronous Transmit FIFO Underflow Interrupt Unmask.
ATFUU
Am79C930
111
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