Date: Fri, 26 Aug 2005 11:39:15 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: User Tomdean <tomdean@speakeasy.org> Cc: freebsd-usb@freebsd.org Subject: Re: Ucom/Uftdi Thru-put Message-ID: <20050826093914.GV37930@cicely12.cicely.de> In-Reply-To: <200508202157.j7KLv1GF005017@asus.tddhome> References: <200508202157.j7KLv1GF005017@asus.tddhome>
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On Sat, Aug 20, 2005 at 02:57:01PM -0700, User Tomdean wrote: > 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? Keep in mind that Full-Speed USB is just 12MBit/s plus much overhead. You are near the theoretical limit. -- B.Walter BWCT http://www.bwct.de bernd@bwct.de info@bwct.de
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