Hello all, We are trying to decide whether or not to purchase a cheap USB host controller to handle a single peripheral device or setup a Spartan 3E 500 gate FPGA to act as the host. .. we are relatively sure that trying to implement Host code on a spartan 3E is a terrible idea... but cannot actually confirm why other than common sense. Could you guys help us out with some reasons why the dedicated host chip or FPGA solution might be better? (code or physical layout might be too difficult?) Thanks in advance khex --------------------------------------- Posted through http://www.EmbeddedRelated.com
USB Interface Chip Vs FPGA Implementation
Started by ●November 15, 2010
Reply by ●November 15, 20102010-11-15
On Nov 16, 4:14=A0pm, "khex" <khexeme1@n_o_s_p_a_m.binghamton.edu> wrote:> Hello all, > > We are trying to decide whether or not to purchase a cheap USB host > controller to handle a single peripheral device or setup a Spartan 3E 500 > gate FPGA to act as the host. > > .. we are relatively sure that trying to implement Host code on a spartan > 3E is a terrible idea... but cannot actually confirm why other than commo=n> sense. > > Could you guys help us out with some reasons why the dedicated host chip =or> FPGA solution might be better? (code or physical layout might be too > difficult?) > > Thanks in advance > > khex > > --------------------------------------- =A0 =A0 =A0 =A0 > Posted throughhttp://www.EmbeddedRelated.comIsn't this answered by the cost of the FPGA resource ? If half the device is sitting there unused, and the project worries more about final cost than engineering time, then a FPGA USB is a good fit. Conversely, if the FPGA is ~full, and adding USB bumps you up to be next device, then it is expensive. Likewise if your project worries more about completion time, than parts costs. -jg
Reply by ●November 16, 20102010-11-16
I'd say go for an external controller chip, unless you are in for the educational experience of designing one. Writing the code (driver + stack) to talk to a device through an external chip already amounts for quite a challenge. Also, I'd consider it a helpful prerequisite before rolling your own fully custom controller.
Reply by ●November 16, 20102010-11-16
On Nov 15, 9:14=A0pm, "khex" <khexeme1@n_o_s_p_a_m.binghamton.edu> wrote:> Hello all, > > We are trying to decide whether or not to purchase a cheap USB host > controller to handle a single peripheral device or setup a Spartan 3E 500 > gate FPGA to act as the host. > > .. we are relatively sure that trying to implement Host code on a spartan > 3E is a terrible idea... but cannot actually confirm why other than commo=n> sense. > > Could you guys help us out with some reasons why the dedicated host chip =or> FPGA solution might be better? (code or physical layout might be too > difficult?) >USB host is mostly about software, the hardware isn't too much different, but there is a lot of s/w involved, especially once you start pulling in drivers for things like the HID class. You might be better served using something like a cpu module that gives you a whole cpu-memory-usb complex and has the code done, then implementing your special stuff in the FPGA.
Reply by ●November 16, 20102010-11-16
On 16 Nov., 15:54, Andy <amd...@gmail.com> wrote:> On Nov 15, 9:14=A0pm, "khex" <khexeme1@n_o_s_p_a_m.binghamton.edu> > wrote: > > > Hello all, > > > We are trying to decide whether or not to purchase a cheap USB host > > controller to handle a single peripheral device or setup a Spartan 3E 5=00> > gate FPGA to act as the host. > > > .. we are relatively sure that trying to implement Host code on a spart=an> > 3E is a terrible idea... but cannot actually confirm why other than com=mon> > sense. > > > Could you guys help us out with some reasons why the dedicated host chi=p or> > FPGA solution might be better? (code or physical layout might be too > > difficult?) > > USB host is mostly about software, the hardware isn't too much > different, but there is a lot of s/w involved, especially once you > start pulling in drivers for things like the HID class. =A0You might be > better served using something like a cpu module that gives you a whole > cpu-memory-usb complex and has the code done, then implementing your > special stuff in the FPGA.I'm sure if you only have to support one specific device you could make a lot of short cuts with the fpga implementation, with the external host chip that might not be so easy, but it will most definitely take more time to get it to work -Lasse
Reply by ●November 16, 20102010-11-16
2010-11-16 04:14, khex skrev:> Hello all, > > We are trying to decide whether or not to purchase a cheap USB host > controller to handle a single peripheral device or setup a Spartan 3E 500 > gate FPGA to act as the host. >Why not get a Microcontroller with USB host? You can either use it as the main processor, or as an auxiliary processor which will handle the USB protocol fully. That is what the "cheap hosts" are doing, but this gives you more flexibility.> .. we are relatively sure that trying to implement Host code on a spartan > 3E is a terrible idea... but cannot actually confirm why other than common > sense. > > Could you guys help us out with some reasons why the dedicated host chip or > FPGA solution might be better? (code or physical layout might be too > difficult?) > > Thanks in advance > > khex > > > > --------------------------------------- > Posted through http://www.EmbeddedRelated.comBest Regards Ulf Samuelsson
Reply by ●November 17, 20102010-11-17
khex <khexeme1@n_o_s_p_a_m.binghamton.edu> wrote:> Hello all,> We are trying to decide whether or not to purchase a cheap USB host > controller to handle a single peripheral device or setup a Spartan 3E 500 > gate FPGA to act as the host.> .. we are relatively sure that trying to implement Host code on a spartan > 3E is a terrible idea... but cannot actually confirm why other than common > sense.> Could you guys help us out with some reasons why the dedicated host chip or > FPGA solution might be better? (code or physical layout might be too > difficult?)Milkymist has a USB Host softcore in XC6SLX -- Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
Reply by ●January 11, 20112011-01-11
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