Psion Teklogix OMNii HDK XT10, Руководство пользователя

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Chapter 4: Software
Omnii HDK API Functions
Psion Teklogix Omnii HDK User Manual 49
4.7.4.15 Hdk7545_ExpansionGetPinState
Syntax
DWORD Hdk7545_ExpansionGetPinState( HANDLE hdk, DWORD pin, Hdk7545_PinState
*state );
Parameters
• hdk – [in] an open HDK handle.
• pin – [in] the ID of the expansion connector pin. The pin parameter must be set to one of the
HDK7545_GPIO_PIN_EXPANSION_xxx values.
• state – [out] pointer to the current pin state.
Description
Retrieves the state of the specified pin.
This function may fail if the pin direction is not set to output (see
“Hdk7545_ExpansionSetPinDirection” on page 41).
Returns
• ERROR_SUCCESS – if successful.
• ERROR_INVALID_HANDLE – the specified handle is invalid.
• ERROR_INVALID_PARAMETER – the specified pin is not valid, or the state pointer is null.
• ERROR_INVALID_DATA - an exception was generated.
• Other errors are possible.
Sample Code
// query the state of a pin, and change it if the state is not clear.
DWORD GetState()
{
Hdk7545_Connector expansionSlot = Hdk7545_Connector_Expansion1;
HANDLE hdkHandle = INVALID_HANDLE_VALUE;
DWORD result = Hdk7545_Open(&hdkHandle, expansionSlot);
if( result != ERROR_SUCCESS ) {
return ERROR_NOT_SUPPORTED;
}
Hdk7545_ExpansionSetPinFunction(hdkHandle,
HDK7545_GPIO_PIN_EXPANSION_GPIO0_TXD,
Hdk7545_PinFunction_GPIO);
Hdk7545_ExpansionSetPinDirection(hdkHandle,
HDK7545_GPIO_PIN_EXPANSION_GPIO0_TXD,
Hdk7545_PinDirection_Output);
Hdk7545_PinState state = Hdk7545_PinState_Unknown;
Hdk7545_ExpansionGetPinState(hdkHandle,
HDK7545_GPIO_PIN_EXPANSION_GPIO0_TXD, &state);
if( state != Hdk7545_PinState_Clr ) {
Hdk7545_ExpansionSetPinState(hdkHandle,
HDK7545_GPIO_PIN_EXPANSION_GPIO0_TXD,
Hdk7545_PinState_Clr);
}
Hdk7545_Close(&hdkHandle);
return ERROR_SUCCESS;
}