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5.2.42 TLEVEL - Transmit FIFO Track Register
Normal Map Read Port = 3:1E
Linked-List Map Read Port = 3:1E
This counter tracks the number of empty bytes in
the transmit FIFO. An empty FIFO has 10h in this
counter. A full FIFO has 00h.
BIT
7
6
5
4
3
2
1
0
TLEVEL
RESET
0
0
0
0
0
0
0
0
—
—
—
CT04
CT03
CT02
CT01
CT00
5.2.43 TSTARTH - Transmit Start Page High
Register
Normal Map Read Port = 2:14
Normal Map Write Port = 0:14
This register is the higher 8 bits of a register pair
that points to the assembled packet to be
transmitted. To retain compatibility with 83C690
drivers, the user should start all frames on 256-byte
boundaries and not write to TSTARTL.
BIT
7
6
5
4
3
2
1
0
TSTARTH
RESET
0
0
0
0
0
0
0
0
A15
A14
A13
A12
A11
A10
A09
A08
5.2.44 TSTARTL - Transmit Start Page Low
Register
Normal Map Read/Write Port = 3:15
Linked-List Map Read/Write Port = 3:15
This register is the lower 8 bits of a register pair that
points to the assembled packet to be transmitted.
To retain compatibility with 83C690 drivers, the user
should start all frames on 256-byte boundaries and
only write to the TSTARTH register.
BIT
7
6
5
4
3
2
1
0
TSTARTL
RESET
0
0
0
0
0
0
0
0
A07
A06
A05
A04
A03
A02
A01
A00
5.2.45 TSTAT - Transmit Status Register
Normal Map Read Port = 0:14
Linked-List Map Read Port = 0:14
The Transmit Status Register reports events that
occur on the media at the end of packet
transmission. All bits are cleared prior to
transmission of a packet and are set as needed.
When ALTEGO = 1, the register is cleared only at
the beginning of a transmit chain and is set after
each packet has completed.
BIT
7
6
5
4
3
2
1
0
TSTAT
RESET
0
0
0
0
0
0
0
0
OWC
CDH
UNDER
CRL
ABORT
TWC
NDT
PTX
Bit 7: OWC
, Out of Window Collision
This bit is set if a collision is detected more than one
slot time after the start of transmission. Transmis-
sion is aborted under these conditions.
83C795
ETHERNET SYSTEM CONTROLLER REGISTERS
38