Adaptec 1737100 Programmer Manual - Page 125

Register Descriptions Bit(s) 7:0 Table 7-66. RxDescQueue1LowAddress Register (Continued) Reset rw value Description/Function r 0 Reserved: Always write 0 RxDescQueue2LowAddress Type: R/W Internal Registers Subgroup: Ethernet Functional Registers Byte Address: E4h - E7h Table 7-67. RxDescQueue2LowAddress Register Reset Bit(s) rw Value Description/Function 31:8 r/w RxDescQ2LowAddress[31:8]: This field indicates the 24 high-order bits of a 32-bit address of the first Receive Buffer Descriptor Queue. The lower 8 bits of the address must be 0. This field is written by host driver during initialization and read by the AIC-6915 during a receive DMA operation. Note: The address must be aligned to 256-byte boundary. 7:0 r 0 Reserved: Always write 0 RxDescQueue1Ptrs Type: R/W Internal Registers Subgroup: Ethernet Functional Registers Byte Address: E8h - EBh Table 7-68. RxDescQueue1Ptrs Register Reset Bit(s) rw Value Description/Function 31:27 r/w 0 Reserved: Always write zero. 26:16 r/w RxDescQ1Consumer: Written by the AIC-6915 and read by host. This field indicates the address of the last descriptor read by the AIC-6915. The software driver should use the ENDINDEX value in the receive completion descriptor rather that this value to determine which buffer the AIC-6915 has used because if the AIC-6915 receives a bad frame, it reverts the consumer back to the beginning of the frame to reuse the buffers. Software can write this field only after setting the RXQ1CONSUMERWE bit in the RXDESCQUEUE1CTRL register. 15:11 r/w 0 Reserved: Always write 0. 10:0 r/w RxDescQ1Producer: Written by host driver and read by the AIC-6915. This field indicates the index value after the last descriptor. 7-53