GD32VF103 User Manual
510
Software should program this field before the channel is enabled. After the transfer
starts, this field is decreased automatically by USBFS after each successful data
packet transmission.
18:0
TLEN[18:0]
Transfer length
The total data bytes number of a transfer.
For OUT transfers, this field is the total data bytes of all the data packets desired to
be transmitted in an OUT transfer. Software should program this field before the
channel is enabled. When software successfully writes a packet into the channel
’s
data TxFIFO, this field is decreased by the byte size of the packet.
For IN transfer each time software or DMA reads out a packet from the RxFIFO, this
field is decreased by the byte size of the packet.
21.7.3.
Device control and status registers
Device configuration register (USBFS_DCFG)
Address offset: 0x0800
Reset value: 0x0000 0000
This register configures the core in device mode after power on or after certain control
commands or enumeration. Do not change this register after device initialization.
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Rese
rve
d
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Rese
rve
d
E
OP
F
T
[1
:0
]
DA
R[6
:0
]
Rese
rve
d
NZ
L
S
OH
DS
[1
:0
]
rw
rw
rw
rw
Bits
Fields
Descriptions
31:13
Reserved
Must be kept at reset value
12:11
EOPFT[1:0]
End of periodic frame time
This field defines the percentage time point in a frame that the end of periodic frame
(EOPF) flag should be triggered.
00: 80% of the frame time
01: 85% of the frame time