projects / libsigrokdecode.git / blame
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| bd0e7d2e SB |
1 | ## |
| 2 | ## This file is part of the libsigrokdecode project. | |
| 3 | ## | |
| 4 | ## Copyright (C) 2015 Stefan Brüns <stefan.bruens@rwth-aachen.de> | |
| 5 | ## | |
| 6 | ## This program is free software; you can redistribute it and/or modify | |
| 7 | ## it under the terms of the GNU General Public License as published by | |
| 8 | ## the Free Software Foundation; either version 2 of the License, or | |
| 9 | ## (at your option) any later version. | |
| 10 | ## | |
| 11 | ## This program is distributed in the hope that it will be useful, | |
| 12 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 14 | ## GNU General Public License for more details. | |
| 15 | ## | |
| 16 | ## You should have received a copy of the GNU General Public License | |
| 17 | ## along with this program; if not, write to the Free Software | |
| 18 | ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
| 19 | ## | |
| 20 | ||
| 21 | ''' | |
| 22 | This decoder stacks on top of the 'usb_packet' PD and decodes the USB | |
| 23 | (low-speed and full-speed) transactions. | |
| 24 | ||
| 25 | Transactions and requests are tracked per device address and endpoint. | |
| 26 | ||
| 27 | Tracking of CONTROL requests is quite accurate, as these always start with | |
| 28 | a SETUP token and are completed by an IN or OUT transaction, the status | |
| 29 | packet. All transactions during the DATA stage are combined. | |
| 30 | ||
| 31 | For BULK and INTERRUPT requests, each transaction starts with an IN or OUT | |
| 32 | request, and is considered completed after the first transaction containing | |
| 33 | data has been ACKed. Normally a request is only completed after a short or | |
| 34 | zero length packet, but this would require knowledge about the max packet | |
| 35 | size of an endpoint. | |
| 36 | ||
| 37 | All INTERRUPT requests are treated as BULK requests, as on the link layer | |
| 38 | both are identical. | |
| 39 | ||
| 40 | The PCAP binary output contains 'SUBMIT' and 'COMPLETE' records. For | |
| 41 | CONTROL request, the SUBMIT contains the SETUP request, the data is | |
| 42 | either contained in the SUBMIT (Host-to-Device) or the COMPLETE | |
| 43 | (Device-to-Host) record. | |
| 44 | ||
| 45 | Details: | |
| 46 | https://en.wikipedia.org/wiki/USB | |
| 47 | http://www.usb.org/developers/docs/ | |
| 48 | ''' | |
| 49 | ||
| 50 | from .pd import Decoder |