ST STM32F40 Series

RM0090 USB on-the-go full-speed (OTG_FS)
Doc ID 018909 Rev 4 1124/1422
Figure 371. Normal interrupt OUT/IN transactions
● 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
Host
Application
DeviceAHB USB
O
U
T
D
A
T
A
0
M
P
S
1
MPS
1
MPS
write_tx_fifo
(ch_1)
init_reg(ch_1)
set_ch_en
(ch_2)
init_reg(ch _2)
write_tx_fifo
(ch_1)
I
N
O
U
T
D
A
T
A
1
M
P
S
Periodic Request Queue
Assume that this queue
can hold 4 entries.
1
5
D
A
T
A
0
I
N
RXFLVL interrupt
1
MPS
read_rx_sts
read_rx_fifo
read_rx_sts
1
2
3
4
6
2
3
6
7
8
9
Odd
(micro)
frame
Even
(micro)
frame
init_reg(ch_1)
set_ch_en
(ch_2)
init_reg(ch _2)
write_tx_fifo
(ch_1)
init_reg(ch_1)
1
MPS
D
A
T
A
1
5
4
A
C
K
A
C
K
A
C
K
ch_1
ch_2
ch_2
ch_1
ai15676
RXFLVL interrupt
XFRC interrupt
XFRC interrupt
XFRC interrupt