To Next Page

To Previous Page

RM0402 Rev 6 1053/1163

RM0402 USB on-the-go full-speed (OTG_FS)

1122

29.15.47 OTG device IN endpoint transmit FIFO status register

(OTG_DTXFSTSx)

Address offset: 0x918 + 0x20 * x, (x = 0 to 5)

Reset value: 0x0000 0200

This read-only register contains the free space information for the device IN endpoint Tx

FIFO.

Bits 20:19 PKTCNT[1:0]: 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[6:0]: 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. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res.

1514131211109876543210

INEPTFSAV[15:0]

rrrrrrrrrrrrrrrr

Bits 31:16 Reserved, must be kept at reset value.

Bits 15:0 INEPTFSAV[15:0]: IN endpoint Tx FIFO space available

Indicates the amount of free space available in the endpoint Tx FIFO.

Values are in terms of 32-bit words:

0x0: Endpoint Tx FIFO is full

0x1: 1 word available

0x2: 2 words available

0xn: n words available

Others: Reserved

ST STM32F412 User Manual

Questions and Answers: