USB on-the-go full-speed (OTG_FS) RM0351
1582/1693 DocID024597 Rev 3
43.15.49 OTG device OUT endpoint 0 transfer size register
(OTG_DOEPTSIZ0)
Address offset: 0xB10
Reset value: 0x0000 0000
The application must modify this register before enabling endpoint 0. Once endpoint 0 is
enabled using the Endpoint enable bit in the OTG_DOEPCTL0 registers (EPENA bit in
OTG_DOEPCTL0), the core modifies this register. The application can only read this
register once the core has cleared the Endpoint enable bit.
Nonzero endpoints use the registers for endpoints 1–5 .
Bits 20:19 PKTCNT: Packet count
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 Tx FIFO.
Bits 18:7 Reserved, must be kept at reset value.
Bits 6:0 XFRSIZ: Transfer size
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 Tx FIFO.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Res. STUPCNT Res. Res. Res. Res. Res. Res. Res. Res. Res.
PKTCNT
Res. Res. Res.
rw rw rw
1514131211109876543210
Res. Res. Res. Res. Res. Res. Res. Res. Res. XFRSIZ
rw rw rw rw rw rw rw
Bit 31 Reserved, must be kept at reset value.
Bits 30:29 STUPCNT: SETUP packet count
This field specifies the number of back-to-back SETUP data packets the endpoint can
receive.
01: 1 packet
10: 2 packets
11: 3 packets
Bits 28:20 Reserved, must be kept at reset value.
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