Device specific known issues and workarounds
===============================================
This page lists known issues and workarounds for specific devices.

NXP LPC54600
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**Severity: High**

**Not recommended for USB device applications (except high-speed host controller)**

Reference: `LPC54600 Errata Sheet`_

.. _LPC54600 Errata Sheet: https://www.nxp.com/docs/en/errata/ES_LPC546XX.pdf

The LPC54600 series have a very buggy USB controller, with 17 issues listed in the errata which is more than half of the total issues.

Most severe issues are:

- USB.2: In USB high-speed device mode, the NBytes field is not correct after BULK IN transfer
- USB.5: In USB full-speed host mode, linked list on done queue is broken.
- USB.15: USB high-speed device in endpoint TX data corruption

WCH CH32F20x/CH32V20x/CH32V30x
---------------------------------
**Severity: Medium**

**Not recommended for USB audio applications**

Reference: `CH32V30X Reference Manual`_ USBFS/USBHS controller chapter

.. _CH32V30X Reference Manual: https://www.wch-ic.com/downloads/CH32FV2x_V3xRM_PDF.html

Data corruption may occur on isochronous endpoints. Due to the lacking of FIFO for interrupt status registers, later completed transfer will overwrite `INT_ST` and `RX_LEN` register if previous transfer processing is not completed.

Other types of transfers are not affected.

Puya PY32F071/072
---------------------------------
**Severity: Very Low**

Reference: `PY32F07x Reference Manual` USBD chapter

The USB device controller (MUSB-like) has 5 application endpoints EP1-EP5 with fixed FIFO sizes
shared between IN and OUT of the same endpoint number: EP1 = 512 B, EP2-4 = 128 B, EP5 = 64 B.
This is much lower than the max ISO ep size of 1024 for high EP numbers.
Place large isochronous endpoints on EP1 and size descriptors accordingly.