Difference between revisions of "CSND Shared Memory"

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Line 13: Line 13:
 
| CommandID
 
| CommandID
 
|-
 
|-
| 0x4-0x7
+
| 0x4
 
| This is initially zero when this command data is written by the user process, once the CSND module finishes processing the command this is set to 0x1.
 
| This is initially zero when this command data is written by the user process, once the CSND module finishes processing the command this is set to 0x1.
 +
|-
 +
| 0x5-0x7
 +
| Padding?
 
|-
 
|-
 
| 0x8-0xB
 
| 0x8-0xB

Revision as of 19:15, 23 August 2013

This page describes the structure of the CSND shared memory.

Type0 Command Structure

Index Byte Description
0x0-0x1 Offset in shared-memory for the command to process immediately after this one, when not 0xFFFF.
0x2-0x3 CommandID
0x4 This is initially zero when this command data is written by the user process, once the CSND module finishes processing the command this is set to 0x1.
0x5-0x7 Padding?
0x8-0xB The low 5-bits for this field is the the channel-index. This word is used for command parameters as well.
0xC-0x1F Command parameters

Type0 Commands

Command 0x8

Index Byte Description
0x2-0x3 CmdID 0x8
0xC-0xF Value for the audio sampling frequency?

This sets the audio sampling frequency?

Command 0xE

Index Byte Description
0x2-0x3 CmdID 0xE
0x14-0x17 Physical address for the audio data.
0x1C-0x1F Total byte-size for the audio data.

This initializes the CSND channel registers located at: 0x1EC03400 + (channel_index*0x20).