Adaptec 1737100 Programmer Manual - Page 126

AIC-6915 Ethernet LAN Controller Programmer's Manual RxDescQueue2Ptrs Type: R/W Internal Registers Subgroup: Ethernet Functional Registers Byte Address: ECh - EFh Table 7-69. RxDescQueue2Ptrs Register Reset Bit(s) rw Value Description/Function 31:27 r/w 0 Reserved: Always write 0. 26:16 r/w 0 RxDescQ2Consumer: 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 RXQ2CONSUMERWE bit in the RXDESCQUEUE2CTRL register. 15:11 r/w 0 Reserved: Always write 0. 10:0 r/w 0 RxDescQ2Producer: Written by the host driver and read by the AIC-6915. This field indicates the index value after the last descriptor. RxDmaStatus Register Type: R/W Internal Registers Subgroup: Ethernet Functional Registers Byte Address: F0h- F3h Table 7-70. RxDmaStatus Register Reset Bit(s) rw Value Description/Function 31:17 r 0 InternalStatus: For diagnostic use only - may change without notice. 16 r 0 NonBurstState: If set, this bit indicates that the RXDMA internal state machine is not in a state where it can start a receive data burst. If RXDMA is disabled, and NONBURSTSTATE is set, the AIC-6915 is guaranteed not to start a new receive data burst until RXDMA is enabled. This bit should be read if the driver wishes to write to RXDMACRC without resetting the AIC-6915. 15:0 r/w 0 RxFramesLostCount: This field indicates the number of frames dropped due to the FIFO being full when no descriptors were available to DMA the data into. 7-54