CD2231 Intel Corporation, CD2231 Datasheet - Page 145

• Manufacturer Part Number: CD2231
• Description: CD2231 Intelligent Two-channel Lan And Wan Communications Controller
• Manufacturer: Intel Corporation

8.6.4.10
8.6.5
8.6.5.1
Datasheet
Register Name: RCBADRU
Register Description: Current Receive Buffer Address, upper word
Default Value: x’0000
Access: Word Read Only
Register Name: ATBADRL
Register Description: Transmit Buffer ‘A’ 32-bit Address, lower word
Default Value: x’0000
Access: Word Read/Write
Bit 15
Bit 15
Bit 7
Bit 7
Receive Current Buffer Address Register — Upper (RCBADRU)
These registers contain the address of the current DMA buffer being used for receive data, updated
at the end of receive data transfers. These registers are for the private use of the CD2231 to manage
DMA transfers. In Asynchronous mode, the host can read this register during a receive exception
interrupt to determine how much data is in the buffer. The address is the location of the next
character to be transferred to the buffer. The host needs this information to process newly arrived
data in the buffer if used in Append mode, and a data timeout has occurred. The address is also
needed if an exception has occurred, and a gap is to be left in the DMA (see the description of the
Gap bits in
bus error during receive data transfer, this register provides the start address of the transfer causing
the bus error.
DMA Transmit Registers
A Transmit Buffer Address Register — Lower (ATBADRL)
Bit 14
Bit 14
Bit 6
Bit 6
Intelligent Two-Channel LAN and WAN Communications Controller — CD2231
Section 8.5.2.7 on page
Bit 13
Bit 13
Bit 5
Bit 5
Binary address value, 32-bit address, bits 31:24
Binary address value, 32-bit address, bits 23:16
Binary address value, 32-bit address, bits 15:8
Binary address value, 32-bit address, bits 7:0
Bit 12
Bit 12
Bit 4
Bit 4
131) for the insertion of status information by the host. For a
Bit 11
Bit 11
Bit 3
Bit 3
Bit 10
Bit 10
Bit 2
Bit 2
Motorola Hex Address: x’3C
Motorola Hex Address: x’52
Bit 9
Bit 1
Bit 9
Bit 1
Intel Hex Address: x’3E
Intel Hex Address: x’50
Bit 8
Bit 0
Bit 8
Bit 0
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