STM32F101xx, STM32F102xx, STM32F103xx, STM32F105xx and ...

RM0008
USB on-the-go full-speed (OTG_FS)
3. When a DISCINT (Disconnect Device) interrupt in OTG_FS_GINTSTS is received.
(The application is expected to disable all enabled channels
4. When the application aborts a transfer before normal completion.
Operational model
The application must initialize a channel before communicating to the connected device.
This section explains the sequence of operation to be performed for different types of USB
transactions.
● Writing the transmit FIFO
The OTG_FS host automatically writes an entry (OUT request) to the periodic/nonperiodic
request queue, along with the last DWORD write of a packet. The application
must ensure that at least one free space is available in the periodic/non-periodic
request queue before starting to write to the transmit FIFO. The application must
always write to the transmit FIFO in DWORDs. If the packet size is non-DWORD
aligned, the application must use padding. The OTG_FS host determines the actual
packet size based on the programmed maximum packet size and transfer size.
Figure 270. Transmit FIFO write task
Read GNPTXSTS/
HPTXFSIZ registers for
available FIFO and
queue spaces
Start
Wait for
TXFELVL or PTXFELVL
interrupt in
OTG_FS_GAHBCFG
No
1 MPS
or LPS FIFO space
available
Yes
Yes
Write 1 packet
data to
Transmit FIFO
More packets
to send
No
MPS: Maximum packet size
LPS: Last t packet size
Done
ai15673
●
Reading the receive FIFO
The application must ignore all packet statuses other than IN data packet (bx0010).
Doc ID 13902 Rev 9 795/995