4.1.3.3 Memory Region R Descriptor Setup Register (0x00000008 + 16×R)
The Memory Region R Descriptor Setup Register (Figure 4-10) is written by the host to configure various descriptor-related parameters of this memory region.
Figure 4-10 Memory Region R Descriptor Setup Register (0x00000008 + 16×R)
Reserved |
DESC_SIZE |
Reserved |
REG_SIZE |
Legend: R = Read only; R/W = Read/Write; - n = value after reset |
Table 4-12 Memory Region R Descriptor Setup Register Field Descriptions
Bit |
Field |
Description |
31-29 |
Reserved |
Reads return 0 and writes have no effect. |
28-16 |
DESC_SIZE |
This field indicates the size of each descriptor in this memory region. The value programmed is the multiplier minus 1 that needs to be applied to 16 to get the actual descriptor size. So, for 16-byte and 64-byte descriptors, the value programmed will be 0 and 3 respectively. |
15-4 |
Reserved |
Reads return 0 and writes have no effect. |
3-0 |
REG_SIZE |
This field indicates the size of the memory region (in terms of number of descriptors). It is an encoded value that specifies region size as 2(5+reg_size) number of descriptors. |