Date: Wed, 30 Apr 2008 18:30:48 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: "Xiaofan Chen" <xiaofanc@gmail.com> Cc: freebsd-usb@freebsd.org Subject: Re: USB Mass Storage Device with HPS Stack Message-ID: <200804301830.49842.hselasky@c2i.net> In-Reply-To: <a276da400804291701n7ab98707gf618e2f0006a5f9a@mail.gmail.com> References: <a276da400804250733v1e8db234x75265d7cfca915c@mail.gmail.com> <200804292159.11467.hselasky@c2i.net> <a276da400804291701n7ab98707gf618e2f0006a5f9a@mail.gmail.com>
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On Wednesday 30 April 2008, Xiaofan Chen wrote: > On Wed, Apr 30, 2008 at 3:59 AM, Hans Petter Selasky <hselasky@c2i.net> wrote: > > Maybe you can get my USB stack working on your PIC board? It now > > supports the Device Side aswell as the host side! See > > "usbd_handle_request" in: > > > > > > http://www.selasky.org/hans_petter/isdn4bsd/sources/src/sys/dev/usb/usb_t > >ransfer.c > > > > Mass storage driver: > > > > > > http://www.selasky.org/hans_petter/isdn4bsd/sources/src/sys/dev/usb/ustor > >age_fs.c > > The PIC18F4550 is a lowly 8-bit MCU (12MIPS, 32KB Flash, 2KB SRAM including > USB RAM). So maybe it is too low to run your USB stack's device side. > What is the minimum requirement to run your USB stack's device side? > Hi, Try and find out. I know that many structures can be optimized for minimal memory usage. Currently I reserve space for 128 USB devices and 32 endpoints and interfaces. If you reduce those numbers then you will save a lot of memory. BTW: When you are out of paper you buy another paper. If the storage in the chip is too small, buy another one. Every line of code is written with a purpose. When you are removing code, like in the software you showed me, then I'm sorry it is not a USB device. Then you have to make your own standard that clearly defines the rules for removal of code. --HPS
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