STM32F101xx, STM32F102xx, STM32F103xx, STM32F105xx and ...

USB on-the-go full-speed (OTG_FS)
RM0008
Figure 274. Normal interrupt OUT/IN transactions
Application
AHB
Host
USB
Device
1
init_reg(ch_1)
init_reg(ch_2)
set_ch_en
(ch_2)
1
2
write_tx_fifo
(ch_1)
1
MPS
3
ch_1
4
Periodic Request Queue
Assume that this queue
can hold 4 entries.
2
3
ch_2
OUT
DATA0
M PS
Odd
(micro)
frame
5
6
XFRC interrupt
ACK
init_reg(ch_1)
4
IN
write_tx_fifo
(ch_1)
1
MPS
5
DATA0
RXFLVL interrupt
read_rx_sts
read_rx_fifo
6
1
MPS
ACK
read_rx_sts
init_reg(ch_2)
set_ch_en
(ch_2)
7 8
9
RXFLVL interrupt
XFRC interrupt
ch_1
ch_2
init_reg(ch_1)
XFRC interrupt
OUT
DATA1
MPS
Even
(micro)
frame
write_tx_fifo
(ch_1)
1
MPS
ACK
IN
DATA1
● Interrupt service routine for interrupt OUT/IN transactions
a) Interrupt OUT
Unmask (NAK/TXERR/STALL/XFRC/FRMOR)
if (XFRC)
{
Reset Error Count
Mask ACK
De-allocate Channel
}
else
if (STALL or FRMOR)
{
Mask ACK
Unmask CHH
ai15676
802/995 Doc ID 13902 Rev 9