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3.19.4 HID Example

The codebase includes an example of a HID volume control implementation based

on ADC data. This code should be considered an example only since an absolute

ADC input does not serve as an ideal input to a relative HID volume control. Buttons

(such as that on the single tile L-Series board) or a Rotary Encoder would be a more

ﬁtting choice of input component.

This code is enabled if

HID_CONTROLS

SU1_ADC_ENABLE

and

ADC_VOL_CONTROL

are all

deﬁned as 1.

The

Vendor_ReadHIDButtons()

function simply looks at the value from the ADC,

if is near the maximum value it reports a volume up, near the minimum value a

volume down is reported. If the ADC value is mid-range no event is reported. The

code is shown below:

void Ven d o r _Rea d H I DButt o n s ( unsigned char hidData [])

{

unsigned adcVal ;

hidData [0] = 0;

# if defined ( A D C_VOL_CO N T R O L ) && ( A D C _ VOL_CON T R O L == 1)

adcVal = g_adcVal >> 20;

if( adcVal < ( ADC_MIN + THRESH ) )

{

/* Volume down */

hidData [0] = 0 x10 ;

}

else if ( adcVal > ( A D C _MAX - T HRESH ) )

{

/* Volume up */

hidData [0] = 0 x08 ;

}

3.19.5 Validated Build Options

The reference design can be built in several ways by changing the build options.

These are described in §5.1.

The design has only been fully validated against the build options as set in the

application as distributed. See §3.1 for details and binary naming scheme.

These fully validated build conﬁgurations are listed below. In practise, due to the

similarities between the U-Series and L-Series feature set, it is fully expected that

all listed U-Series conﬁgurations will operate as expected on the L-Series and vice

versa.

REV 6.1

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