Re: USB transfer rate LPC17xx

Started by linnix May 14, 2011
On May 14, 2:35=A0pm, Andrew Jackson <a...@nospam.com> wrote:
> On 14/05/2011 17:29, linnix wrote: > > > On May 14, 9:12 am, "navman"<naveen_pn@n_o_s_p_a_m.yahoo.com> =A0wrote: > >> Hi, > >> We are designing a device which needs to transfer data to a PC over US=
B
> >> continuously. We plan to use the LPC1768 Cortex-M3 processor for this > >> application. We would like some opinion on the best approach for the U=
SB
> >> class implementation. We are looking at about 400Kbytes/sec sustainabl=
e
> >> transfer rate between the device to PC. The reverse traffic will be qu=
ite
> >> lean. > > > We get over 500KB/s with a 32mHz PIC24, so M3 should be doable. > > However, we are using asynchronous ACK/NAK protocols. > > I don't think that you mean that do you?
Yes, full speed bandwidth is 12M, 500K is around 4M.
>=A0USB 2.0 high speed can manage > a maximum 480Mbps but the actual rate is less allowing for turn-arounds, > inter-packet gaps, etc.
That why we need asynch. bulk transfer. Max. transfer is to internal SRAM only, 96K for 1/5 of a second.
On 15/05/2011 00:02, linnix wrote:
> On May 14, 2:35 pm, Andrew Jackson<a...@nospam.com> wrote: >> On 14/05/2011 17:29, linnix wrote: >> >>> On May 14, 9:12 am, "navman"<naveen_pn@n_o_s_p_a_m.yahoo.com> wrote: >>>> Hi, >>>> We are designing a device which needs to transfer data to a PC over USB >>>> continuously. We plan to use the LPC1768 Cortex-M3 processor for this >>>> application. We would like some opinion on the best approach for the USB >>>> class implementation. We are looking at about 400Kbytes/sec sustainable >>>> transfer rate between the device to PC. The reverse traffic will be quite >>>> lean. >> >>> We get over 500KB/s with a 32mHz PIC24, so M3 should be doable. >>> However, we are using asynchronous ACK/NAK protocols. >> >> I don't think that you mean that do you? > > Yes, full speed bandwidth is 12M, 500K is around 4M.
Apologies, brain fade! Andrew