Universal serial bus full-speed device interface (USB) RM0008
626/1096 Doc ID 13902 Rev 12
Transmission byte count n (USB_COUNTn_TX)
Address offset: [USB_BTABLE] + n*16 + 4
USB local Address: [USB_BTABLE] + n*8 + 2
Note: Double-buffered and Isochronous IN Endpoints have two USB_COUNTn_TX
registers: named USB_COUNTn_TX_1 and USB_COUNTn_TX_0 with the
following content.
Reception buffer address n (USB_ADDRn_RX)
Address offset: [USB_BTABLE] + n*16 + 8
USB local Address: [USB_BTABLE] + n*8 + 4
151413121110987654321 0
Reserved
COUNTn_TX[9:0]
rw rw rw rw rw rw rw rw rw rw
Bits 15:10 These bits are not used since packet size is limited by USB specifications to 1023 bytes. Their
value is not considered by the USB peripheral.
Bits 9:0 COUNTn_TX[9:0]: Transmission byte count
These bits contain the number of bytes to be transmitted by the endpoint associated with the
USB_EPnR register at the next IN token addressed to it.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Reserved
COUNTn_TX_1[9:0]
rw rw rw rw rw rw rw rw rw rw
151413121110987654321 0
Reserved
COUNTn_TX_0[9:0]
rw rw rw rw rw rw rw rw rw rw
1514131211109876543210
ADDRn_RX[15:1] -
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw -
Bits 15:1 ADDRn_RX[15:1]: Reception buffer address
These bits point to the starting address of the packet buffer, which will contain the data
received by the endpoint associated with the USB_EPnR register at the next OUT/SETUP
token addressed to it.
Bit 0 This bit must always be written as ‘0 since packet memory is word-wide and all packet buffers
must be word-aligned.