SDIO_Control 0 (changes)
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SDIODriver
» SWI Calls
» SDIO_Control
» SDIO_Control 0
SDIO_Control 0
(SWI &59001)
| Entry | |
|---|---|
| R0 | 0 (reason code) |
| R1 | Bits 0 – 7 = slot number |
| Bits 8 – 15 = bus number |
| Exit | |
|---|---|
| Error &81EE06 (“Slot in use”) is returned if exclusive access cannot be acquired at the present time | |
Use
This SWI is used to acquire exclusive access to slot, non-blocking.
Re-entrancy
This SWI is re-entrant.
Notes
This call is one of a group that must be used around every call to SWI SDIO_Op. The reason for this is that many SD commands need to be issued in groups of two or more. If another SD command is queued in the middle of such a group, it may find that the device is not in a receptive state for that command, and the operation of the command group that was interrupted may also be disrupted.
This version of the acquire-slot SWI is suitable for use from the background, but the caller must be prepared for it to fail and reschedule the command at a later time.
See also
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