CD2231 Intel Corporation, CD2231 Datasheet - Page 148

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CD2231

Manufacturer Part Number
CD2231
Description
CD2231 Intelligent Two-channel Lan And Wan Communications Controller
Manufacturer
Intel Corporation
Datasheet
CD2231 — Intelligent Two-Channel LAN and WAN Communications Controller
8.6.5.8
148
Register Name: BTBSTS
Register Description: Transmit Buffer ‘B’ Status
Default Value: x’00
Access: Byte Read/Write
Register Name: ATBSTS
Register Description: Transmit Buffer ‘A’ Status
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 7
Berr
Berr
B Transmit Buffer Status (BTBSTS) — Async-HDLC/PPP Mode
Bit 7
Bit 6
Bit 5
Bits 4:3
Bit 2
Bit 1
Bit 0
To start transmission of a buffer, the host must set the ATBADR/BTBADR (Transmit Buffer
Address) and ATBCNT/BTBCNT (Transmit Buffer Count) registers, and then set the 2231own bit.
If the CD2231 is to generate and send the CRC for the frame, the CRC bit in COR1 must be set. If
the buffer contains the end of a frame, the EOF bit must also be set. When the buffer has been sent,
the EOB bit is set by the CD2231, and 2231own is reset, allowing a new buffer to be allocated.
A Transmit Buffer Status (ATBSTS) — SLIP/MNP 4 Mode
Bit 6
EOF
EOF
Bit 6
Berr – Bus error (set by the CD2231, and cleared by the host)
0 = No bus error
1 = Bus error was detected on the last transfer
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.
EOB – The end of a transmit buffer (set by the CD2231, and cleared by the host).
The end of a host supplied transmit buffer has been reached.
Reserved – must be ‘0’.
map32 – Map all transmit characters from 00–1F (set and cleared by the host)
0 = Use the normal TXACCM map.
1 = Map all characters in the range from 00–1F.
INTR – Interrupt
0 = No interrupt required after the buffer is transmitted.
1 = Interrupt required after the buffer is transmitted.
2231own – Ownership of the transmit buffer (set by the host and cleared by the
CD2231)
0 = Buffer is owned by the host, and not ready for use by the CD2231.
1 = Buffer is owned by the CD2231, and is ready for use by the CD2231.
EOB
EOB
Bit 5
Bit 5
Bit 4
Bit 4
0
0
Bit 3
Bit 3
0
0
map32
Bit 2
Bit 2
0
Motorola Hex Address: x’5E
Motorola Hex Address: x’5F
INTR
INTR
Bit 1
Bit 1
Intel Hex Address: x’5D
Intel Hex Address: x’5C
Datasheet
2231own
2231own
Bit 0
Bit 0

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