hplcc2420spip.nc

tinyos2.0版本驱动

/*
 * Copyright (c) 2005 Arch Rock Corporation
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 *   its contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 */

/**
 * Automatic slave select update for the SpiResource
 *
 * @author Miklos Maroti
 */

module HplCC2420SpiP
{
	provides interface Resource;
  
	uses
	{
		interface Resource as SubResource;	// raw SPI resource
		interface GeneralIO as SS;			// Slave set line
	}
}

implementation
{
	async command error_t Resource.request()
	{
		return call SubResource.request();
	}

	async command error_t Resource.immediateRequest()
	{
		error_t error = call SubResource.immediateRequest();
		if( error == SUCCESS )
		{
			call SS.makeOutput();
			call SS.clr();
		}
		return error;
	}

	event void SubResource.granted()
	{
		call SS.makeOutput();
		call SS.clr();

		signal Resource.granted();
	}
	
	async command error_t Resource.release()
	{
		if( call SubResource.isOwner() )
			call SS.set();

		return call SubResource.release();
	}

	async command bool Resource.isOwner()
	{
		return call SubResource.isOwner();
	}
}