HS_USB 2.0 device
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Doc ID 018672 Rev 1
23.5 Data
memory
structure in DMA mode
23.5.1
SETUP data memory structure
The memory structure for SETUP data is given in
. The 16-byte buffer consists of 4
fields of 32 bits each: the status quadlet (its bit assignments are given in
), a
reserved one and the 2 last fields for the 8 bytes of SETUP data.
Figure 46.
SETUP data memory
Table 389. SETUP data memory: status quadlet bit assignments
Bit
Name
Description
[31:30]
BS
Buffer status.
This 2 bit field reports the status of the SETUP data buffer, according to
encoding:
– 2‘b00 Host ready. = The descriptor is available to be processed by DMA.
– 2‘b01 DMA busy. = The DMA is still processing the descriptor.
– 2‘b10 DMA done. = Buffer data transfer completed by DMA.
– 2‘b11 Host busy. = The application is processing the descriptor.
[29:28]
Rx Sts
Receive status.
This 2 bit field reports the status of the received SETUP data (according to
encoding), reflecting whether the SETUP data has been correctly received or
some errors occurred:
– 2‘b00 = Success.
– 2‘b01 = DESERR (descriptor transfer error).
– 2‘b10 = Reserved.
– 2‘b11 = BUFFER (data transfer error).
[27:16]
Config Sts
Configuration status.
This 12 bit field echoes the status of the current configuration associated
with the SETUP packet for a control endpoint. Bits assignments for this field
are given:
– [27:24] = Configuration number.
– [23:20] = Interface number.
– [19:16] = Alternate setting number.
[15:00]
Reserved
Read: undefined. Write: should be zero.
Setup Buffer Pointer
Status Quadlet
Reserved
First 4 Bytes of Setup Data
Second 4 Bytes of Setup Data
Status Quadlet
Config Sts
R
BS
Rx Sts
15:0
27:16
29:28
31:30
0
31