13.5.1 Descriptor Format

A descriptor is a 32-bit entry in a Descriptor Table. It consists of three sections based on the functionality as follows:

  • Payload Pointer: SADDRn[15:0]/DADDRn[15:0]
  • Transfer Size: SIZEn[1:0]
  • Descriptor Pointer Offset: DPOnM1[6:0], DPOnM0[6:0]

The structure of a Descriptor Table is as follows:

Table 13-9. Descriptor Table
Memory PositionDescriptor
[31:25][24:18][17:16][15:0]
1DPO1M1[6:0]DPO1M0[6:0]SIZE1[1:0]Payload Pointer
2DPO2M2[6:0]DPO2M0[6:0]SIZE2[1:0]Payload Pointer
3DPO3M3[6:0]DPO3M0[6:0]SIZE3[1:0]Payload Pointer
......