/**
 * Texas Instruments HDQ implementation for the Arduino API
 * (cleft) Matthieu Lalonde 2008 (matth@mlalonde.net)
 * Creative Commons BY-SA-NC
 * 
 * http://trac.mlalonde.net/cral/browser/HDQ/
 * 
 * Revision 1
 *
**/

#ifndef _HDQ_H_
#define _HDQ_H_
	
	/**
	 * Default pin to use if none is specified to the constructor
	**/
	#define HDQ_DEFAULT_PIN			7 /* Arduino pin 7 */
	
	/**
	 * Read/write command mask
	**/
	#define HDQ_ADDR_MASK_READ		0x00
	#define HDQ_ADDR_MASK_WRITE		0x80 /* B10000000 */
	
	/**
	 * HDQ bit timings
	**/
	#define HDQ_DELAY_BIT_START		30
	#define HDQ_DELAY_BIT_WRITE		100
	#define HDQ_DELAY_BIT_END		70
	#define HDQ_DELAY_BIT_TOTAL		200
	
	/**
	 * This is the number of times the slave wait loop
	 * will run before we time out.
	 * As far as I can tell the loop uses ~6 instructions
	 * thus giving about 200uS delay which is a full bit write
	**/
	#define HDQ_DELAY_FAIL_TRIES	225
	
	/**
	 * HDQ Default timings
	**/
	#define HDQ_DELAY_TB			250	/* Min: 190uS */
	#define HDQ_DELAY_TBR			50	/* Min: 40uS */
	#define HDQ_DELAY_TSTRH			1	/* Min: 5nS */
	#define HDQ_DELAY_TDSU			50	/* Max: 50uS */
	#define HDQ_DELAY_TDH			100	/* Min: 100uS */
	#define HDQ_DELAY_TSSU			145 /* Max: 145uS */
	#define HDQ_DELAY_TCYCH			190	/* Min: 190uS */
	#define HDQ_DELAY_TSTRB			32	/* Min: 32uS */
	#define HDQ_DELAY_TDSUB			50	/* Max: 50uS */
	#define HDQ_DELAY_TDV			80	/* Min 80uS */
	#define HDQ_DELAY_TSSUB			145	/* Max: 145uS */
	#define HDQ_DELAY_TCYCB_MIN		190	/* Min: 190uS */
	#define HDQ_DELAY_TCYCB_MAX		250	/* Max: 250uS */
	#define HDQ_DELAY_TRSPS_MIN		190	/* Min: 190uS */
	#define HDQ_DELAY_TRSPS_MAX		320	/* Max: 320uS */
	#define HDQ_DELAY_TRSPS_DIFF	130 /* HDQ_DELAY_TRSPS_MAX - HDQ_DELAY_TRSPS_MIN */
	
	class HDQ
	{
	public:
		/**
		 * Constructor
		 * @param pinArg: pin number to attach to
		**/
		HDQ(uint8_t pinArg = HDQ_DEFAULT_PIN);
		
		/**
		 * sendBreak: writes a break to the HDQ line
		**/
		void doBreak(void);
		
		/**
		 * write: send a payload to the device
		 * @param reg: the address of the register to write to
		 * @param payload: data to be sent
		 * @return: false, unless if verif is set, then 
		 * 			it will read back the register and 
		 * 			return true if it matches the payload
		**/
		boolean write(uint8_t reg, uint8_t payload, boolean verif);
		boolean write(uint8_t reg, uint8_t payload);
		
		/**
		 * read: read from the device
		 * @param register: address of the register to read
		 * @return a uint8_t integer
		**/
		uint8_t read(uint8_t reg);
		
	private:
		/**
		 * Port variables definition
		**/
		uint8_t pin;
		uint8_t port;
		uint8_t bitmask;
		volatile uint8_t *outputReg;
		volatile uint8_t *inputReg;
		volatile uint8_t *modeReg;
		
		/**
		 * writeByte: write a raw byte of data to the bus
		 * @param payload: the byte to send
		 * 
		**/
		void writeByte(uint8_t payload);
};
#endif