#include <twl/spi.h>u32 PM_SetAmpGainLevel( u8 level );
u32 PM_SetAmpGainLevelAsync( u8 level, PMCallback callback, void* arg );
| level | Setting value that determines the amp gain. |
| callback | Callback that is called when the command finishes. |
| arg | Argument that is used when calling the callback. |
If PM_RESULT_SUCCESS, the command execution has succeeded (for synchronous functions), or the command was successfully sent to the ARM7 processor (for asynchronous functions).
If PM_RESULT_BUSY, the SPI was occupied by other processing and unable to process this function.
Sets the gain of the programmable amp gain. This function can only be used when the operating mode is TWL mode.
The level argument is a u8 value; specify a value in the range of 0 to 119.
Differences Between the PM_SetAmpGain* and PM_SetAmpGainLevel* Functions
There are two types of setter functions: PM_SetAmpGain* and PM_SetAmpGainLevel*. The former has existed since the Nintendo DS and can specify four gain levels. The latter is explained in this reference page; it is new, has been added for the TWL system, and can set 120 gain levels.
The PM_SetAmpGain* functions can specify four levels and are usable in any mode. The specified value is always set unchanged.
The PM_SetAmpGainLevel* functions can specify 120 levels and are usable only in TWL HYBRID and TWL LIMITED mode. The CODEC mode decides whether the value is actually configured as one of 120 levels, as specified. When the CODEC is running in TWL mode (which should always be the operating mode in this case), a 120-level specification is set, unchanged, to 120 levels. However, at all other times, values specified for 120 levels will be averaged to 4 levels. These four levels conform to the four levels set with the PM_SetAmpGain function.
Value of level and the Gain to Set
The value of the level argument and the actual amp gain that is set are shown below.
When the codec is in TWL mode:
level Gain to Set 0 10.5 dB 1 11.0 dB 2 11.5 dB : : n 10.5 + (n x 0.5) dB : : 119 70.0 dB
When the codec is in DS mode:
level Gain to Set 0 ~ 36 26.0 dB (equivalent to 31 in the 120-level notation) 37 ~ 48 32.0 dB (equivalent to 43 in the 120-level notation) 49 ~ 60 38.0 dB (equivalent to 55 in the 120-level notation) 61 ~ 119 44.0 dB (equivalent to 67 in the 120-level notation)
Asynchronous Functions
This function uses PXI to send the command that performs the corresponding operation in the ARM7 processor. The ARM7 side that receives that command is executed by operating the PMIC. Therefore, this function may not operate instantly after you call it. A synchronous function that waits for the operation to finish, as well as an asynchronous function that only sends commands to the ARM7, are provided. Use either of the functions depending on your operational requirements. (The asynchronous function has "Async" appended to the function name.)
When an asynchronous function is called, the specified callback is called when processing on the ARM7 side finishes. The callback type PMCallback is defined by:
typedef void ( *PMCallback )( u32 result, void* arg );
This callback is called from inside the PXI interrupt handler.
The callback's first argument, result, indicates the result of the command. This is either PM_RESULT_SUCCESS or PM_RESULT_BUSY. The second argument in the callback returns the value arg.
About PM_RESULT_BUSY
The SPI is used for various other processes besides power management. If you call this function while another process is using it, this function sends a command to the ARM7. There, the SPI is determined to be BUSY, and PM_RESULT_BUSY is dispatched to the ARM9 without actually processing this function. Likewise, if you call this function while another PM process is running, that fact is determined on the ARM9, and this function returns PM_RESULT_BUSY. (In this case, the determination is made before notification is sent to the ARM7.)
Accordingly, if you want to ensure that this function succeeds, make it loop until it succeeds as shown below. (This example does not take into account mistakes such as wrong arguments.)
Example
while( PM_SetAmpGainLevel( ... ) != PM_RESULT_SUCCESS )
{
}
When using the Async version of this function, you could do this with code similar to the following.
Example
void setResult( u32 result, void* arg )
{
if ( arg )
{
*(u32*)arg = result;
}
}
while(1)
{
volatile u32 result = PM_RESULT_NONE; // Value that is not returned as a result
while ( PM_SetAmpGainLevelAsync(..., setResult, (void*)&result ) != PM_RESULT_SUCCESS )
{
}
// Some other process
otherProcess();
// Wait for processing to finish
while( result == PM_RESULT_NONE )
{
}
// Exit from the loop on success
if ( result == PM_RESULT_SUCCESS )
{
break;
}
}
On NITRO hardware, this function manipulates the PMIC register PGA_GAIN. On TWL hardware it manipulates the codec.
PM_Init
PM_SetAmp*
PM_SetAmpGain*
PM_GetAmpGainLevel
2009/06/03 Removed a description of the PM_Init function (because OS_Init is now required).
2008/05/01 Initial version. Branched off from the PM_SetAmpGain* functions.
CONFIDENTIAL