Problem Description: When a packet of exactly 64 Bytes is transmitted using USBUART from PSoC to a PC and the result observed on a Terminal program, nothing is displayed on the Terminal program on the PC. Reason and Workaround: This is because of a bug in the USBUART User module code. The firmware is supposed to send a zero length packet after sending the 64 byte packet. The driver in the PC will know of the reception of the string only after receiving this zero length packet. As the firmware does not send the zero length packet, the PC driver is not aware of the reception of the data. This problem occurs only for a packet of exactly 64 characters. Packets with other lengths are received fine. The workaround for this problem is to split the 64 byte packet into two packets of any lengths, for example 32 + 32, or 62 + 2 etc. This problem will be fixed in PSD5.0 SP6, which is expected by the end of September 2009.
The date on this "fix" is 2009 or 2010 depending where I look. I have the same problem today running the USB UART datasheet example project with the cyc8kit-050 using USBFS.2.6. Is there still noreal fix?