On Fri, Feb 26, 2010 at 12:38 AM, m. allan noah <kitno455 at gmail.com> wrote: > Do you find that the machine actually makes any control packets once > it starts scanning? Many scanners only use those at initial > configuration, which is taken care of by the host OS, and calls to set > interface, etc. I have found that I generally only use bulk packets > with most scanners...
Hello, Yes, so it would appear, also in this case. Attached is the gzipped usbsnoop output of a 75-dpi B/W (or greyscale, not sure) scan of 2 inches wide by 1 inches high sheet of white paper, after passing log output through spike4. The configuration was done before that, and there do not appear to be any other control packets since then. I imagine that is good news. I haven't analysed the spiked output yet to see what is sent and what is received (Stef recommended checking for possible firmware sending but there did not seem to be anything sent during the initial configuration when scanner is attached to the host). Two questions, from reading the USB specs so far: 1) in usbsnoop endpoint numbers show up as 0, 7 (bulk OUT), 88 (bulk IN), and 89 (interrupt IN). But there are only 4 bits for endpoint numbers (maximum of 15 extra endpoints for IN and another 15 for OUT). So do the endpoint numbers include some other bits also to give such high numbers? 2) I'm confused what the order of bits is in usbsnoop output. I understand a display in LSB order means LSB is Bit0, and is given on the leftmost side, as in Bit0, Bit1, Bit2... and Bit0 is transferred out first in the serial protocol. So if I have usbsnoop data like the Vid, Pid, Rev: 12 01 00 02 00 00 00 40 a9 04 01 19 01 01 02 the order of bytes received is from left to right (I assume!) but for each byte, is the LSB representation for (e.g., a9) like this (0=LSB, 7=MSB): 0 1 2 3 4 5 6 7 1 0 0 1 0 1 0 1 or like this: 0 1 2 3 4 5 6 7 0 1 0 1 1 0 0 1 I assume the latter, if the data are visually a string of 0 and 1 conveniently grouped in hex representation. Best regards, Gernot Hassenpflug -------------- next part -------------- A non-text attachment was scrubbed... Name: usbsnoop-scan.txt.gz Type: application/x-gzip Size: 33256 bytes Desc: not available URL: <http://lists.alioth.debian.org/pipermail/sane-devel/attachments/20100226/9b6850b4/attachment-0001.bin>
