simpleSA/pE4302.h

/*
 *	"PE4302.h"
 *
 *	Added to the "TinySA" program in Version 1.1 by John Price (WA2FZW):
 *
 *	This is the header file for the PE4302 class.
 */

#ifndef PE4302_H_
#define PE4302_H_							// Prevent double inclusion

#include <Arduino.h>						// General Arduino definitions
#include <Wire.h>							// I2C library
#include <SPI.h>              // Serial Peripheral Interface library
#include "simpleSA.h"   

/*
 *	In order to save GPIO pins on the ESP32, Glenn (VK3PE) and I decided to use a 
 *	PCF8574 GPIO expander chip between the processor and the parallel version of
 *	of the PE4302 attenuator. We know some PE4302 modules are available with a
 *	serial interface, but the ones we happen to have only support the parallel
 *	interface. This lets us control it over the I2C bus.
 *
 *	It's not clear to me that the native serial interface to the serial module 
 *	is an I2C interface, but we will also support that via a bit-banging techique.
 *	We will also support the parallel interface module without the PCF8574.
 */

enum	{ PCF, P, S };					// Symbols for operational modes

class PE4302
{
public:

/*
 *	Function prototypes for the PE4302 available to the outside world:
 *
 *	Constructors:
 */

explicit	PE4302 ( SPIClass* spi, int le );		// For serial interface
explicit	PE4302 ( int address );						// For PCF8574 interface
explicit	PE4302 ( int c16, int c8, int c4,			// For parallel interface
					 int c2,  int c1, int c0 );

void	Init ();									// Initialize the module
bool	SetAtten ( int8_t atten );					// Set the attenuation
int		GetAtten ();								// Get the current attenuation


private:

uint8_t		_pcf_I2C;				// I2C address for the PCF8574

uint8_t		_interface;				// Interface type ( PCF, P or S )

uint8_t		_le_Pin;				// Enable (LE) pin for serial or parallel interdace

uint8_t		_parallel_Pins[6];		// Pin numbers ( c0 - c16 ) for parallel interface

int16_t		_atten;					// Current attenuator setting ( 0 - 31 dB ) x 2
SPIClass*   _spi;          // Pointer to the SPI object used for serial mode

};


/*
 *	This is a stripped down version of the PCF8574 library. We only need the
 *	constructor, the "begin" function (slightly modified from the original
 *	library), the "write8" functions and a couple of the variables.
 */

class PCF8574
{

public:

	explicit PCF8574 ( const uint8_t deviceAddress );
	void begin ( const uint8_t deviceAddress, uint8_t val );
	void write8 ( const uint8_t value );

private:

	uint8_t _address;						// PCF8574 I2C address
	uint8_t _dataOut;						// Data to be sent
};

#endif