Ucom/Uftdi Thru-put

[User Tomdean]

I am running FreeBSD 5.4 on an ASUS A7N266E.

I have a FTDI FT8U245BM based UMP2 driven by an Atmel ATmega16, connected to ucom0.

usb0: OHCI version 1.0
usb0: <OHCI (generic) USB controller> on ohci0
usb0: USB revision 1.0
uhub0: nVidia OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 3 ports with 3 removable, self powered
ohci1: <OHCI (generic) USB controller> mem 0xee800000-0xee800fff irq 21 at device 3.0 on pci0
usb1: OHCI version 1.0
usb1: <OHCI (generic) USB controller> on ohci1
usb1: USB revision 1.0
uhub1: nVidia OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub1: 3 ports with 3 removable, self powered
...
ucom0: FTDI USB HS Serial Converter, rev 1.10/2.00, addr 2

The FT8U245BM looks like an FT8U232AM, except the 'other side' is
parallel rather than serial.  From the EEPROM,

vendor  0x0403    == USB_VENDOR_FTDI
product 0x6001    == USB_PRODUCT_FTDI_SERIAL_8U232AM
release 0x0200

My FreeBSD process just loops, reading ucom0.  The microprocessor just
loops, waiting for space in the UMP2 transmit buffer, 'TXE#' then writes an
'a'.

The thru-put is 1000060 bytes in 32.26 seconds or about 31 KBytes/sec.

The microprocessor spends most of the time waiting for TXE#.

Is this near the max thru-put of the uftdi driver?

tomdean