Files
lib_xua/module_usb_aud_shared/endpoint0/descriptors_2.rst
2011-07-07 20:15:51 +01:00

59 lines
2.9 KiB
ReStructuredText

Descriptors in XMOS USB Audio
=============================
ADAT Alternate Settings
-----------------------
6 interfaces
endpoint can only be shared between alternate settings of the same interface (not between interfaces)
change alternate settings via SET_INTERFACE request
an alternate setting has its' own interface and endpoint descriptors
+-----------+------+-------+----------------+--------------------------------------------------+
| interface | type | alt. | endps. | note |
+-----------+------+-------+----------------+--------------------------------------------------+
| 0 | AC | irq_in | |
+-----------+------+-------+----------------+--------------------------------------------------+
| 1 | AS | 0 | | null interface |
| | +-------+----------------+--------------------------------------------------+
| | | 1 | iso_out iso_in | 18 channels, host -> device, iso_in is feedback |
| | +-------+----------------+--------------------------------------------------+
| | | 2 | shared | 18 channels |
+-----------+------+-------+----------------+--------------------------------------------------+
| 2 | AS | 0 | | null interface |
| | +-------+----------------+--------------------------------------------------+
| | | 1 | iso_in | 18 channels, device -> host |
| | +-------+----------------+--------------------------------------------------+
| | | 2 | shared | 14 channels |
+-----------+------+-------+----------------+--------------------------------------------------+
| 3 | AC | | MIDI |
+-----------+------+-------+----------------+--------------------------------------------------+
| 4 | MS | bul_out bul_in | |
+-----------+------+-------+----------------+--------------------------------------------------+
| 5 | DFU | | |
+-----------+------+-------+----------------+--------------------------------------------------+
Interface 1: host -> device
Interface 2: device -> host
Structure of defines::
alt 0
alt 1
18 ch
#ifdef ADAT
alt 2
14 ch
#endif
Inconsistencies
---------------
- is MIDI AC interface is required? spec says 1 AC interface per function
- interface association descriptor specifies 3 interfaces, but there are 6