UPSD3422_06 Datasheet, PDF (289/293 Pages) STMicroelectronics – Turbo Plus Series Fast Turbo 8032 MCU with USB and Programmable Logic

uPSD34xx
Important notes
implemented then this extra and unexpected data packet would result in a communication
breakdown.
Workaround
Revision A and B - In the USB ISR, when an INx (x = the endpoint number of the IN FIFO)
interrupt is detected, the IN FIFOs respective busy bit should be unconditionally cleared.
The uPSD3400 USB firmware implements this workaround.
34.7
IN FIFO Pairing Operation
Description
When FIFO pairing is used on IN endpoints, an erroneous resend of a data packet may
occur. See the "Erroneous Resend of Data Packet" note as it also applies when IN FIFO
pairing is used.
Impact On Application
See the "Erroneous Resend of Data Packet" note as the impact is the same when IN FIFO
pairing is used.
Workaround
Revision A and B - See the "Erroneous Resend of Data Packet" note as the workaround is
the same when IN FIFO pairing is used.
34.8
OUT FIFO Pairing Operation
Description
When data packets are received from the host and FIFO pairing is used, the paired FIFOs
may get out of order.
Impact On Application
The received data packets are read out of order compared to the way they were sent from
the host. If the workaround is not implemented, the out of order packets would result in a
communication breakdown.
Workaround
Revision A and B - In the USB ISR, when an OUTx (x = the endpoint number of the OUT
FIFO) interrupt is detected, the OUT FIFOs respective busy bit should be unconditionally
cleared. The uPSD3400 USB firmware implements this workaround.
34.9
Missing ACK to host retransmission of SETUP packet
Description
If a host does not properly receive the ACK (due to noise) from the uPSD3400 in response
to a SETUP packet, it will resend the SETUP packet but the uPSD3400 will not respond with
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