Fujitsu MJA2500BH Maintenance Manual - Page 91
DMA Setup - Device to Host or Host to Device Bidirectional, DMA Setup - Device
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5.2 Logical Interface 5.2.3.5 DMA Setup - Device to Host or Host to Device (Bidirectional) The DMA Setup - Device to Host or Host to Device FIS has the following layout: 33222222222211111111119876543210 1098765432109876543210 0 Reserved (0) Reserved (0) A I D Reserved (0) FIS Type (41h) 0 1 TAG 2 0 3 Reserved (0) DMA Buffer Offset 4 5 DMA Transfer Count 6 Reserved (0) Figure 5.7 DMA Setup - Device to Host or Host to Device FIS layout The DMA Setup - Device to Host or Host to Device FIS communicates the start of a first-party DMA access to the host system. This FIS is used to request the host system or device to set up the DMA controller before the start of a DMA data transfer. A - Auto Active bit. If this bit is cleared ("0" is set for the bit), it indicates that a DMA Active FIS transfer is required before a Data FIS transfer. D - Direction bit. If this bit is set ("1" is set for the bit), it indicates that the data transfer direction is from the device to the host system. C141-E293 5-17