HCDMA4 

         Host Channel 4 DMA Address Register
Module Instance Base Address Register Address
i_usbotg_0_DWC_otg_intreg 0xFFB00000 0xFFB00594
i_usbotg_1_DWC_otg_intreg 0xFFB40000 0xFFB40594

Size: 32

Offset: 0x594

Access: RW

Important: The value of a reserved bit must be maintained in software. When you modify registers containing reserved bit fields, you must use a read-modify-write operation to preserve state and prevent indeterminate system behavior.
Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

DMAAddr

RW 0x0

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

DMAAddr

RW 0x0

HCDMA4 Fields

Bit Name Description Access Reset
31:0 DMAAddr 

Buffer DMA Mode:
[31:0] DMA Address (DMAAddr)
This field holds the start address in the external memory from which the data for 
the endpoint must be fetched or to which it must be stored. This register is 
incremented on every AHB transaction.

Scatter-Gather DMA (DescDMA) Mode:
[31:9] (Non Isoc) Non-Isochronous: 
[31:N] (Isoc) Isochronous: 
This field holds the start address of the 512 bytes  
page.  The first descriptor in the list should be located 
in this address. The first descriptor may be or may 
not be ready. The core starts processing the list from 
the CTD value. 
This field holds the address of the 2*(nTD+1) bytes of 
locations in which the isochronous descriptors are 
present where N is based on nTD as per Table below

 [31:N]  Base Address
[N-1:3]  Offset
  [2:0]  000

HS ISOC
nTD   N
7     6
15    7
31    8
63    9
127  10
255  11

FS ISOC
nTD N
 1  4
 3  5
 7  6
15  7
31  8
63  9

[N-1:3] (Isoc):
[8:3] (Non Isoc): Current Transfer Desc(CTD):  
Non Isochronous: 
This value is in terms of number of descriptors. The values can be from 0 to 63. 
 0 -  1 descriptor. 
63 - 64 descriptors. 
This field indicates the current descriptor processed in the list. This field is updated 
both by application and the core. For example, if the application enables the 
channel after programming CTD=5, then the core will start processing the 6th 
descriptor. The address is obtained by adding a value of (8bytes*5=) 40(decimal)  
to DMAAddr.  
Isochronous: 
CTD for isochronous is based on the current frame/(micro)frame value. Need to be set 
to zero by application.Scatter-Gather DMA (DescDMA) Mode:
[31:9] (Non Isoc) Non-Isochronous: 
[31:N] (Isoc) Isochronous: 
This field holds the start address of the 512 bytes  
page.  The first descriptor in the list should be located 
in this address. The first descriptor may be or may 
not be ready. The core starts processing the list from 
the CTD value. 
This field holds the address of the 2*(nTD+1) bytes of 
locations in which the isochronous descriptors are 
present where N is based on nTD as per Table below

 [31:N]  Base Address
[N-1:3]  Offset
  [2:0]  000

HS ISOC
nTD   N
7     6
15    7
31    8
63    9
127  10
255  11

FS ISOC
nTD N
 1  4
 3  5
 7  6
15  7
31  8
63  9

[N-1:3] (Isoc):
[8:3] (Non Isoc): Current Transfer Desc(CTD):  
Non Isochronous: 
This value is in terms of number of descriptors. The values can be from 0 to 63. 
 0 -  1 descriptor. 
63 - 64 descriptors. 
This field indicates the current descriptor processed in the list. This field is updated 
both by application and the core. For example, if the application enables the 
channel after programming CTD=5, then the core will start processing the 6th 
descriptor. The address is obtained by adding a value of (8bytes*5=) 40(decimal)  
to DMAAddr.  
Isochronous: 
CTD for isochronous is based on the current frame/(micro)frame value. Need to be set 
to zero by application.
 RW 0x0