ST STM32F413 Reference Manual page 1184

USB on-the-go full-speed (OTG_FS)
Bit 19 PKTCNT: Packet count
Bits 18:7 Reserved, must be kept at reset value.
Bits 6:0 XFRSIZ: Transfer size
33.15.48 OTG device IN endpoint-x transfer size register (OTG_DIEPTSIZx)
(x = 1..5, where x= Endpoint_number)
Address offset: 0x910 + (Endpoint_number × 0x20)
Reset value: 0x0000 0000
The application must modify this register before enabling the endpoint. Once the endpoint is
enabled using the Endpoint enable bit in the OTG_DIEPCTLx registers (EPENA bit in
OTG_DIEPCTLx), the core modifies this register. The application can only read this register
once the core has cleared the Endpoint enable bit.
31 30 29
Res. MCNT
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15 14 13
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Bit 31 Reserved, must be kept at reset value.
Bits 30:29 MCNT: Multi count
Bits 28:19 PKTCNT: Packet count
Bits 18:0 XFRSIZ: Transfer size
1184/1284
This field is decremented to zero after a packet is written into the Rx FIFO.
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 is read from the Rx FIFO and written to
the external memory.
28 27 26 25
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12 11 10 9
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For periodic IN endpoints, this field indicates the number of packets that must be transmitted
per frame on the USB. The core uses this field to calculate the data PID for isochronous IN
endpoints.
01: 1 packet
10: 2 packets
11: 3 packets
Indicates the total number of USB packets that constitute the Transfer Size amount of data
for this endpoint.
This field is decremented every time a packet (maximum size or short packet) is read from
the Tx FIFO.
This field contains the transfer size in bytes for the current endpoint. The core only interrupts
the application 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.
24 23 22
PKTCNT
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8 7 6
XFRSIZ
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DocID029473 Rev 3
21 20 19 18
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5 4 3 2
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RM0430
17 16
XFRSIZ
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1 0
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