GigaDevice Semiconductor GD32F3x0 - Page 637

GD32F3x0 User Manual
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2
1
0
TLEN[15:0]
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Bits
Fields
Descriptions
31
Reserved
Must be kept at reset value
30:29
DPID[1:0]
Data PID
Software should write this field before the transfer starts. For OUT transfers, this field
controls the Data PID of the first transmitted packet. For IN transfers, this field controls
the expected Data PID of the first received packet, and DTERR will be triggered if the
Data PID doesn’t match. After the transfer starts, USBFS changes and toggles this field
automatically following the USB protocol.
00: DATA0
10: DATA1
11: SETUP (For control transfer only)
01: Reserved
28:19
PCNT[9:0]
Packet count
The number of data packets desired to be transmitted (OUT) or received (IN) in a
transfer.
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 byte 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 reads out a packet from the RxFIFO, this field is
decreased by the byte size of the packet.
23.7.3. 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