DIEPTSIZ12

         Device IN Endpoint 12 Transfer Size Register
      
Module Instance Base Address Register Address
i_usbotg_0_DWC_otg_intreg 0xFFB00000 0xFFB00A90
i_usbotg_1_DWC_otg_intreg 0xFFB40000 0xFFB40A90

Size: 32

Offset: 0xA90

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

RESERVED

RO 0x0

MC

RW 0x0

PktCnt

RW 0x0

XferSize

RW 0x0

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

XferSize

RW 0x0

DIEPTSIZ12 Fields

Bit Name Description Access Reset
31 RESERVED
RESERVED
RO 0x0
30:29 MC
Applies to IN endpoints only.
For periodic IN endpoints, this field indicates the number of packets that must be transmitted per microframe on the USB. The core uses this field to calculate the data PID for isochronous IN endpoints. 
  2'b01: 1 packet 
  2'b10: 2 packets 
  2'b11: 3 packets 
For non-periodic IN endpoints, this field is valid only in Internal DMA mode. It specifies the number of packets the core must fetchfor an IN endpoint before it switches to the endpoint pointed to by the Next Endpoint field of the Device Endpoint-n Control register (DIEPCTLn.NextEp)
Value Description
0x1 1 packet
0x2 2 packets
0x3 3 packets
RW 0x0
28:19 PktCnt
Packet Count (PktCnt)
Indicates the total number of USB packets that constitute the
Transfer Size amount of data For endpoint 0.
This field is decremented every time a packet (maximum size or
short packet) is read from the TxFIFO.
RW 0x0
18:0 XferSize
Transfer Size (XferSize)
Indicates the transfer size in bytes For endpoint 0. The core
interrupts the application only after it has exhausted the transfer
size amount of data. The transfer size can be Set to the
maximum packet size of the endpoint, to be interrupted at the
end of each packet.
The core decrements this field every time a packet from the
external memory is written to the TxFIFO.
RW 0x0