
Programmable Four-Channel Communications Controller
—
CD2481
Datasheet
195
0 = Buffer is owned by the host, and not ready for use by the CD2481.
1 = Buffer is owned by the CD2481, and is ready for use by the CD2481.
9.6.5.13
A Transmit Buffer Status (ATBSTS)
–
SLIP/MNP4 Mode
9.6.5.14
B Transmit Buffer Status (BTBSTS)
–
SLIP/MNP4 Mode
Bit 7
Berr
–
Bus error (set by the CD2481, and cleared by the host)
0 = No bus error.
1 = Bus error was detected on the last transfer.
Bit 6
EOF
–
End of Frame (set and cleared by the host)
0 = This buffer is not the last in frame/block.
1 = This buffer is the last in frame/block.
Bit 5
EOB
–
The end of a transmit buffer has been reached
(set by the CD2481, and cleared by the host)
The end of a host supplied transmit buffer has been reached.
Bits 4:2
Reserved
–
must be zero
.
Bit 1
INTR
–
Interrupt
0 = No interrupt required after the buffer is transmitted.
1 = Interrupt required after the buffer is transmitted.
Bit 0
2481own
–
Ownership of the transmit buffer (set by the host and cleared by the
CD2481)
0 = Buffer is owned by the host, and not ready for use by the CD2481.
1 = Buffer is owned by the CD2481, and is ready for use by the CD2481.
Register Name: ATBSTS
Register Description: Transmit Buffer
‘
A
’
Status Register
Default Value: x
’
00
Access: Byte Read/Write
Intel Hex Address: x
’
5C
Motorola Hex Address: x
’
5F
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Berr
EOF
EOB
0
0
0
INTR
2481own
Register Name: BTBSTS
Register Description: Transmit Buffer
‘
B
’
Status Register
Default Value: x
’
00
Access: Byte Read/Write
Intel Hex Address: x
’
5D
Motorola Hex Address: x
’
5E
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Berr
EOF
EOB
0
0
0
INTR
2481own