Si4737_i2c.h

/* UWAFT Si4737 

Adopted from:
Arduino Si4735 (and family) Library
* See the README file for author and licensing information. In case it's
* missing from your distribution, use the one here as the authoritative
* version: https://github.com/csdexter/Si4735/blob/master/README
*/

#ifndef Si4737_i2c_h
#define Si4737_i2c_h

# include <Arduino.h>

//BEWARE - CONSTANTS RETAIN THE OLD SI4735 PREFIX!

//Assign the default radio pin numbers (shield version)
#define SI4735_PIN_POWER 27
#define SI4735_PIN_RESET 9
#define SI4735_PIN_GPO2 29

//List of possible interfaces for Si4735
#define SI4735_INTERFACE_SPI 0
#define SI4735_INTERFACE_I2C 1

//Assign the SPI pin numbers (shield version)
//SDIO, GPO1 and SCLK always connected to MOSI, MISO and SCK for SPI mode
//SDIO and SCLK always connected to SDA and SCL for I2C mode
//SEN should be hardwired HIGH or LOW for I2C mode
#define SI4735_PIN_SEN SS

//Constants for hardwired pins
//Chip is always powered, do not use PIN_POWER semantics
#define SI4735_PIN_POWER_HW 0xFF
//Chip interfaced via I2C, GPO2 left floating or tied LOW
//Define both HW and HWL constants to suit both semantics when typing
#define SI4735_PIN_GPO2_HW 0xFF
#define SI4735_PIN_GPO2_HWL 0xFF
//Chip interfaced via I2C, SEN always HIGH, device address 0xC6
#define SI4735_PIN_SEN_HWH 0xFF
//Chip interfaced via I2C, SEN always LOW, device address 0x22
#define SI4735_PIN_SEN_HWL 0xFE

//List of possible modes for the Si4735 Radio
#define SI4735_MODE_NONE 0
#define SI4735_MODE_FM 1
#define SI4735_MODE_AM 2
#define SI4735_MODE_WB 3

//List default property values
#define SI4735_DEFAULT_FM_BLEND_MONO_THRESHOLD 30
#define SI4735_DEFAULT_FM_BLEND_STEREO_THRESHOLD 49
#define SI4735_DEFAULT_FM_BLEND_RSSI_MONO_THRESHOLD 30
#define SI4735_DEFAULT_FM_BLEND_RSSI_STEREO_THRESHOLD 49

//Define the Locale options
#define SI4735_LOCALE_US 0
#define SI4735_LOCALE_EU 1

//Define Si47xx Command codes
#define SI4735_CMD_POWER_UP 0x01
#define SI4735_CMD_GET_REV 0x10
#define SI4735_CMD_POWER_DOWN 0x11
#define SI4735_CMD_SET_PROPERTY 0x12
#define SI4735_CMD_GET_PROPERTY 0x13
#define SI4735_CMD_GET_INT_STATUS 0x14
#define SI4735_CMD_PATCH_ARGS 0x15
#define SI4735_CMD_PATCH_DATA 0x16
#define SI4735_CMD_FM_TUNE_FREQ 0x20
#define SI4735_CMD_FM_SEEK_START 0x21
#define SI4735_CMD_FM_TUNE_STATUS 0x22
#define SI4735_CMD_FM_RSQ_STATUS 0x23
#define SI4735_CMD_FM_RDS_STATUS 0x24
#define SI4735_CMD_FM_AGC_STATUS 0x27
#define SI4735_CMD_FM_AGC_OVERRIDE 0x28
#define SI4735_CMD_TX_TUNE_FREQ 0x30
#define SI4735_CMD_TX_TUNE_POWER 0x31
#define SI4735_CMD_TX_TUNE_MEASURE 0x32
#define SI4735_CMD_TX_TUNE_STATUS 0x33
#define SI4735_CMD_TX_ASQ_STATUS 0x34
#define SI4735_CMD_TX_RDS_BUF 0x35
#define SI4735_CMD_TX_RDS_PS 0x36
#define SI4735_CMD_AM_TUNE_FREQ 0x40
#define SI4735_CMD_AM_SEEK_START 0x41
#define SI4735_CMD_AM_TUNE_STATUS 0x42
#define SI4735_CMD_AM_RSQ_STATUS 0x43
#define SI4735_CMD_AM_AGC_STATUS 0x47
#define SI4735_CMD_AM_AGC_OVERRIDE 0x48
#define SI4735_CMD_WB_TUNE_FREQ 0x50
#define SI4735_CMD_WB_TUNE_STATUS 0x52
#define SI4735_CMD_WB_RSQ_STATUS 0x53
#define SI4735_CMD_WB_SAME_STATUS 0x54
#define SI4735_CMD_WB_ASQ_STATUS 0x55
#define SI4735_CMD_WB_AGC_STATUS 0x57
#define SI4735_CMD_WB_AGC_OVERRIDE 0x58
#define SI4735_CMD_AUX_ASRC_START 0x61
#define SI4735_CMD_AUX_ASQ_STATUS 0x65
#define SI4735_CMD_GPIO_CTL 0x80
#define SI4735_CMD_GPIO_SET 0x81

//Define Si4735 Command flags (bits fed to the chip)
#define SI4735_FLG_CTSIEN 0x80
//Renamed to GPO2IEN from GPO2OEN in datasheet to avoid conflict with real
//GPO2OEN below. Also makes more sense this way: GPO2IEN -> enable GPO2 as INT
//GPO2OEN -> enable GPO2 generically, as an output
#define SI4735_FLG_GPO2IEN 0x40
#define SI4735_FLG_PATCH 0x20
#define SI4735_FLG_XOSCEN 0x10
#define SI4735_FLG_FREEZE 0x02
#define SI4735_FLG_FAST 0x01
#define SI4735_FLG_SEEKUP 0x08
#define SI4735_FLG_WRAP 0x04
#define SI4735_FLG_CANCEL 0x02
#define SI4735_FLG_INTACK 0x01
#define SI4735_FLG_STATUSONLY 0x04
#define SI4735_FLG_MTFIFO 0x02
#define SI4735_FLG_GPO3OEN 0x08
#define SI4735_FLG_GPO2OEN 0x04
#define SI4735_FLG_GPO1OEN 0x02
#define SI4735_FLG_GPO3LEVEL 0x08
#define SI4735_FLG_GPO2LEVEL 0x04
#define SI4735_FLG_GPO1LEVEL 0x02
#define SI4735_FLG_BLETHA_0 0x00
#define SI4735_FLG_BLETHA_12 0x40
#define SI4735_FLG_BLETHA_35 0x80
#define SI4735_FLG_BLETHA_U (SI4735_FLG_BLETHA_12 | SI4735_FLG_BLETHA_35)
#define SI4735_FLG_BLETHB_0 SI4735_FLG_BLETHA_0
#define SI4735_FLG_BLETHB_12 0x10
#define SI4735_FLG_BLETHB_35 0x20
#define SI4735_FLG_BLETHB_U (SI4735_FLG_BLETHB_12 | SI4735_FLG_BLETHB_35)
#define SI4735_FLG_BLETHC_0 SI4735_FLG_BLETHA_0
#define SI4735_FLG_BLETHC_12 0x04
#define SI4735_FLG_BLETHC_35 0x08
#define SI4735_FLG_BLETHC_U (SI4735_FLG_BLETHC_12 | SI4735_FLG_BLETHC_35)
#define SI4735_FLG_BLETHD_0 SI4735_FLG_BLETHA_0
#define SI4735_FLG_BLETHD_12 0x01
#define SI4735_FLG_BLETHD_35 0x02
#define SI4735_FLG_BLETHD_U (SI4735_FLG_BLETHD_12 | SI4735_FLG_BLETHD_35)
#define SI4735_FLG_RDSEN 0x01
#define SI4735_FLG_DEEMPH_NONE 0x00
#define SI4735_FLG_DEEMPH_50 0x01
#define SI4735_FLG_DEEMPH_75 0x02
#define SI4735_FLG_RSQREP 0x08
#define SI4735_FLG_RDSREP 0x04
#define SI4735_FLG_STCREP 0x01
#define SI4735_FLG_ERRIEN 0x40
#define SI4735_FLG_RSQIEN 0x08
#define SI4735_FLG_RDSIEN 0x04
#define SI4735_FLG_STCIEN 0x01
#define SI4735_FLG_RDSNEWBLOCKB 0x20
#define SI4735_FLG_RDSNEWBLOCKA 0x10
#define SI4735_FLG_RDSSYNCFOUND 0x04
#define SI4735_FLG_RDSSYNCLOST 0x02
#define SI4735_FLG_RDSRECV 0x01
#define SI4735_FLG_AMPLFLT 0x01
#define SI4735_FLG_AMCHFLT_6KHZ 0x00
#define SI4735_FLG_AMCHFLT_4KHZ 0x01
#define SI4735_FLG_AMCHFLT_3KHZ 0x02
#define SI4735_FLG_AMCHFLT_2KHZ 0x03
#define SI4735_FLG_AMCHFLT_1KHZ 0x04
#define SI4735_FLG_AMCHFLT_1KHZ8 0x05
#define SI4735_FLG_AMCHFLT_2KHZ5 0x06

//Define Si4735 Function modes
#define SI4735_FUNC_FM 0x00
#define SI4735_FUNC_AM 0x01
#define SI4735_FUNC_WB 0xC3 //RIC The name should be 4737

//Define Si4735 Output modes
#define SI4735_OUT_RDS 0x00 // RDS only
#define SI4735_OUT_ANALOG 0x05
#define SI4735_OUT_DIGITAL1 0x0B // DCLK, LOUT/DFS, ROUT/DIO
#define SI4735_OUT_DIGITAL2 0xB0 // DCLK, DFS, DIO
#define SI4735_OUT_BOTH (SI4735_OUT_ANALOG | SI4735_OUT_DIGITAL2)

//Define Si47xx Status flag masks (bits the chip fed us)
#define SI4735_STATUS_CTS 0x80
#define SI4735_STATUS_ERR 0x40
#define SI4735_STATUS_RSQINT 0x08
#define SI4735_STATUS_RDSINT 0x04
#define SI4735_STATUS_ASQINT 0x02
#define SI4735_STATUS_STCINT 0x01
#define SI4735_STATUS_BLTF 0x80
#define SI4735_STATUS_AFCRL 0x02
#define SI4735_STATUS_VALID 0x01
#define SI4735_STATUS_BLENDINT 0x80
#define SI4735_STATUS_MULTHINT 0x20
#define SI4735_STATUS_MULTLINT 0x10
#define SI4735_STATUS_SNRHINT 0x08
#define SI4735_STATUS_SNRLINT 0x04
#define SI4735_STATUS_RSSIHINT 0x02
#define SI4735_STATUS_RSSILINT 0x01
#define SI4735_STATUS_SMUTE 0x08
#define SI4735_STATUS_PILOT 0x80
#define SI4735_STATUS_OVERMOD 0x04
#define SI4735_STATUS_IALH 0x02
#define SI4735_STATUS_IALL 0x01

//Define Si47xx Property codes
#define SI4735_PROP_GPO_IEN word(0x0001)
#define SI4735_PROP_DIGITAL_INPUT_FORMAT 0x0101
#define SI4735_PROP_DIGITAL_OUTPUT_FORMAT 0x0102
#define SI4735_PROP_DIGITAL_INPUT_SAMPLE_RATE 0x0103
#define SI4735_PROP_DIGITAL_OUTPUT_SAMPLE_RATE 0x0104
#define SI4735_PROP_REFCLK_FREQ 0x0201
#define SI4735_PROP_REFCLK_PRESCALE 0x0202
#define SI4735_PROP_FM_DEEMPHASIS 0x1100
#define SI4735_PROP_FM_CHANNEL_FILTER 0x1102
#define SI4735_PROP_FM_BLEND_STEREO_THRESHOLD 0x1105
#define SI4735_PROP_FM_BLEND_MONO_THRESHOLD 0x1106
#define SI4735_PROP_FM_ANTENNA_INPUT 0x1107
#define SI4735_PROP_FM_MAX_TUNE_ERROR 0x1108
#define SI4735_PROP_FM_RSQ_INT_SOURCE 0x1200
#define SI4735_PROP_FM_RSQ_SNR_HI_THRESHOLD 0x1201
#define SI4735_PROP_FM_RSQ_SNR_LO_THRESHOLD 0x1202
#define SI4735_PROP_FM_RSQ_RSSI_HI_THRESHOLD 0x1203
#define SI4735_PROP_FM_RSQ_RSSI_LO_THRESHOLD 0x1204
#define SI4735_PROP_FM_RSQ_MULTIPATH_HI_THRESHOLD 0x1205
#define SI4735_PROP_FM_RSQ_MULTIPATH_LO_THRESHOLD 0x1206
#define SI4735_PROP_FM_RSQ_BLEND_THRESHOLD 0x1207
#define SI4735_PROP_FM_SOFT_MUTE_RATE 0x1300
#define SI4735_PROP_FM_SOFT_MUTE_SLOPE 0x1301
#define SI4735_PROP_FM_SOFT_MUTE_MAX_ATTENUATION 0x1302
#define SI4735_PROP_FM_SOFT_MUTE_SNR_THRESHOLD 0x1303
#define SI4735_PROP_FM_SOFT_MUTE_RELEASE_RATE 0x1304
#define SI4735_PROP_FM_SOFT_MUTE_ATTACK_RATE 0x1305
#define SI4735_PROP_FM_SEEK_BAND_BOTTOM 0x1400
#define SI4735_PROP_FM_SEEK_BAND_TOP 0x1401
#define SI4735_PROP_FM_SEEK_FREQ_SPACING 0x1402
#define SI4735_PROP_FM_SEEK_TUNE_SNR_THRESHOLD 0x1403
#define SI4735_PROP_FM_SEEK_TUNE_RSSI_THRESHOLD 0x1404
#define SI4735_PROP_FM_RDS_INT_SOURCE 0x1500
#define SI4735_PROP_FM_RDS_INT_FIFO_COUNT 0x1501
#define SI4735_PROP_FM_RDS_CONFIG 0x1502
#define SI4735_PROP_FM_RDS_CONFIDENCE 0x1503
#define SI4735_PROP_FM_AGC_ATTACK_RATE 0x1700
#define SI4735_PROP_FM_AGC_RELEASE_RATE 0x1701
#define SI4735_PROP_FM_BLEND_RSSI_STEREO_THRESHOLD 0x1800
#define SI4735_PROP_FM_BLEND_RSSI_MONO_THRESHOLD 0x1801
#define SI4735_PROP_FM_BLEND_RSSI_ATTACK_RATE 0x1802
#define SI4735_PROP_FM_BLEND_RSSI_RELEASE_RATE 0x1803
#define SI4735_PROP_FM_BLEND_SNR_STEREO_THRESHOLD 0x1804
#define SI4735_PROP_FM_BLEND_SNR_MONO_THRESHOLD 0x1805
#define SI4735_PROP_FM_BLEND_SNR_ATTACK_RATE 0x1806
#define SI4735_PROP_FM_BLEND_SNR_RELEASE_RATE 0x1807
#define SI4735_PROP_FM_BLEND_MULTIPATH_STEREO_THRESHOLD 0x1808
#define SI4735_PROP_FM_BLEND_MULTIPATH_MONO_THRESHOLD 0x1809
#define SI4735_PROP_FM_BLEND_MULTIPATH_ATTACK_RATE 0x180A
#define SI4735_PROP_FM_BLEND_MULTIPATH_RELEASE_RATE 0x180B
#define SI4735_PROP_FM_BLEND_MAX_STEREO_SEPARATION 0x180C
#define SI4735_PROP_FM_NB_DETECT_THRESHOLD 0x1900
#define SI4735_PROP_FM_NB_INTERVAL 0x1901
#define SI4735_PROP_FM_NB_RATE 0x1902
#define SI4735_PROP_FM_NB_IIR_FILTER 0x1903
#define SI4735_PROP_FM_NB_DELAY 0x1904
#define SI4735_PROP_FM_HICUT_SNR_HIGH_THRESHOLD 0x1A00
#define SI4735_PROP_FM_HICUT_SNR_LOW_THRESHOLD 0x1A01
#define SI4735_PROP_FM_HICUT_ATTACK_RATE 0x1A02
#define SI4735_PROP_FM_HICUT_RELEASE_RATE 0x1A03
#define SI4735_PROP_FM_HICUT_MULTIPATH_TRIGGER_THRESHOLD 0x1A04
#define SI4735_PROP_FM_HICUT_MULTIPATH_END_THRESHOLD 0x1A05
#define SI4735_PROP_FM_HICUT_CUTOFF_FREQUENCY 0x1A06
#define SI4735_PROP_TX_COMPONENT_ENABLE 0x2100
#define SI4735_PROP_TX_AUDIO_DEVIATION 0x2101
#define SI4735_PROP_TX_PILOT_DEVIATION 0x2102
#define SI4735_PROP_TX_RDS_DEVIATION 0x2103
#define SI4735_PROP_TX_LINE_INPUT_LEVEL 0x2104
#define SI4735_PROP_TX_LINE_INPUT_MUTE 0x2105
#define SI4735_PROP_TX_PREEMPHASIS 0x2106
#define SI4735_PROP_TX_PILOT_FREQUENCY 0x2107
#define SI4735_PROP_TX_ACOMP_ENABLE 0x2200
#define SI4735_PROP_TX_ACOMP_THRESHOLD 0x2201
#define SI4735_PROP_TX_ACOMP_ATTACK_TIME 0x2202
#define SI4735_PROP_TX_ACOMP_RELEASE_TIME 0x2203
#define SI4735_PROP_TX_ACOMP_GAIN 0x2204
#define SI4735_PROP_TX_LIMITER_RELEASE_TIME 0x2205
#define SI4735_PROP_TX_ASQ_INTERRUPT_SOURCE 0x2300
#define SI4735_PROP_TX_ASQ_LEVEL_LOW 0x2301
#define SI4735_PROP_TX_ASQ_DURATION_LOW 0x2302
#define SI4735_PROP_TX_ASQ_LEVEL_HIGH 0x2303
#define SI4735_PROP_TX_ASQ_DURATION_HIGH 0x2304
#define SI4735_PROP_TX_RDS_INTERRUPT_SOURCE 0x2C00
#define SI4735_PROP_TX_RDS_PI 0x2C01
#define SI4735_PROP_TX_RDS_PS_MIX 0x2C02
#define SI4735_PROP_TX_RDS_PS_MISC 0x2C03
#define SI4735_PROP_TX_RDS_PS_REPEAT_COUNT 0x2C04
#define SI4735_PROP_TX_RDS_PS_MESSAGE_COUNT 0x2C05
#define SI4735_PROP_TX_RDS_PS_AF 0x2C06
#define SI4735_PROP_TX_RDS_FIFO_SIZE 0x2C07
#define SI4735_PROP_AM_DEEMPHASIS 0x3100
#define SI4735_PROP_AM_CHANNEL_FILTER 0x3102
#define SI4735_PROP_AM_AUTOMATIC_VOLUME_CONTROL_MAX_GAIN 0x3103
#define SI4735_PROP_AM_MODE_AFC_SW_PULL_IN_RANGE 0x3104
#define SI4735_PROP_AM_MODE_AFC_SW_LOCK_IN_RANGE 0x3105
#define SI4735_PROP_AM_RSQ_INTERRUPTS 0x3200
#define SI4735_PROP_AM_RSQ_SNR_HIGH_THRESHOLD 0x3201
#define SI4735_PROP_AM_RSQ_SNR_LOW_THRESHOLD 0x3202
#define SI4735_PROP_AM_RSQ_RSSI_HIGH_THRESHOLD 0x3203
#define SI4735_PROP_AM_RSQ_RSSI_LOW_THRESHOLD 0x3204
#define SI4735_PROP_AM_SOFT_MUTE_RATE 0x3300
#define SI4735_PROP_AM_SOFT_MUTE_SLOPE 0x3301
#define SI4735_PROP_AM_SOFT_MUTE_MAX_ATTENUATION 0x3302
#define SI4735_PROP_AM_SOFT_MUTE_SNR_THRESHOLD 0x3303
#define SI4735_PROP_AM_SOFT_MUTE_RELEASE_RATE 0x3304
#define SI4735_PROP_AM_SOFT_MUTE_ATTACK_RATE 0x3305
#define SI4735_PROP_AM_SEEK_BAND_BOTTOM 0x3400
#define SI4735_PROP_AM_SEEK_BAND_TOP 0x3401
#define SI4735_PROP_AM_SEEK_FREQ_SPACING 0x3402
#define SI4735_PROP_AM_SEEK_TUNE_SNR_THRESHOLD 0x3403
#define SI4735_PROP_AM_SEEK_TUNE_RSSI_THRESHOLD 0x3404
#define SI4735_PROP_AM_AGC_ATTACK_RATE 0x3702
#define SI4735_PROP_AM_AGC_RELEASE_RATE 0x3703
#define SI4735_PROP_AM_FRONTEND_AGC_CONTROL 0x3705
#define SI4735_PROP_AM_NB_DETECT_THRESHOLD 0x3900
#define SI4735_PROP_AM_NB_INTERVAL 0x3901
#define SI4735_PROP_AM_NB_RATE 0x3902
#define SI4735_PROP_AM_NB_IIR_FILTER 0x3903
#define SI4735_PROP_AM_NB_DELAY 0x3904
#define SI4735_PROP_RX_VOLUME 0x4000
#define SI4735_PROP_RX_HARD_MUTE 0x4001
#define SI4735_PROP_WB_MAX_TUNE_ERROR 0x5108
#define SI4735_PROP_WB_RSQ_INT_SOURCE 0x5200
#define SI4735_PROP_WB_RSQ_SNR_HI_THRESHOLD 0x5201
#define SI4735_PROP_WB_RSQ_SNR_LO_THRESHOLD 0x5202
#define SI4735_PROP_WB_RSQ_RSSI_HI_THRESHOLD 0x5203
#define SI4735_PROP_WB_RSQ_RSSI_LO_THRESHOLD 0x5204
#define SI4735_PROP_WB_VALID_SNR_THRESHOLD 0x5403
#define SI4735_PROP_WB_VALID_RSSI_THRESHOLD 0x5404
#define SI4735_PROP_WB_SAME_INTERRUPT_SOURCE 0x5500
#define SI4735_PROP_WB_ASQ_INTERRUPT_SOURCE 0x5600
#define SI4735_PROP_AUX_ASQ_INTERRUPT_SOURCE 0x6600

//Define RDS-related public flags (that may come handy to the user)
#define SI4735_RDS_DI_STEREO 0x01
#define SI4735_RDS_DI_ARTIFICIAL_HEAD 0x02
#define SI4735_RDS_DI_COMPRESSED 0x04
#define SI4735_RDS_DI_DYNAMIC_PTY 0x08

//This holds the current station reception metrics as given by the chip. See
//the Si4735 datasheet for a detailed explanation of each member.
typedef struct {
	byte STBLEND;
	bool PILOT;
	byte RSSI;
	byte SNR;
	byte MULT;
	signed char FREQOFF;
} Si4737_RX_Metrics;

//This holds time of day as received via RDS. Mimicking struct tm from
//<time.h> for familiarity.
//NOTE: RDS does not provide seconds, only guarantees that the minute update
//      will occur close enough to the seconds going from 59 to 00 to be
//      meaningful -- so we don't provide tm_sec
//NOTE: RDS does not provide DST information so we don't provide tm_isdst
//NOTE: we will provide tm_wday (day of week) but not tm_yday (day of year)
typedef struct {
	byte tm_min;
	byte tm_hour;
	byte tm_mday;
	byte tm_mon;
	word tm_year;
	byte tm_wday;
}  Si4737_RDS_Time;

typedef struct {
	//PI is already taken :-(
	word programIdentifier;
	bool TP, TA, MS;
	byte PTY, DICC;
	char programService[9];
	char programTypeName[51];
	char radioText[65];
} Si4737_RDS_Data;

//BEWARE - CLASSES ARE CALLED Si4737!

class Si4737RDSDecoder
{
public:
	/*
	* Description:
	*   Default constructor.
	*/
	Si4737RDSDecoder() { resetRDS(); }

	/*
	* Description:
	*   Decodes one RDS block and updates internal data structures.
	*/
	void decodeRDSBlock(word block[]);

	/*
	* Description:
	*   Returns currently decoded RDS data, filling a struct
	*   Si4735_RDS_Data.
	*/
	void getRDSData(Si4737_RDS_Data* rdsdata);

	/*
	* Description:
	*   Returns currently decoded RDS CT information filling a struct
	*   Si4735_RDS_Time, if any is available, and returns true; otherwise
	*   returns false and does not touch rdstime.
	* Parameters:
	*   rdstime - pointer to a struct Si4735_RDS_Time to be filled with
	*             CT information, ignore if only interested in CT
	*             availability and not actual value.
	*/
	bool getRDSTime(Si4737_RDS_Time* rdstime = NULL);

	/*
	* Description:
	*   Resets internal data structures, use when switching to a new
	*   station.
	*/
	void resetRDS(void);

#if defined(SI4735_DEBUG)
	/* Description:
	*    Dumps RDS group type receipt statistics.
	*/
	void dumpRDSStats(void);
#endif

private:
	Si4737_RDS_Data _status;
	Si4737_RDS_Time _time;
	bool _rdstextab, _rdsptynab, _havect;
#if defined(SI4735_DEBUG)
	word _rdsstats[32];
#endif
	/*
	* Description:
	*   Filters the string str in place to only contain printable
	*   characters and also replaces 0x0D (CR) with 0x00 effectively
	*   ending the string at that point as per RDBS ¡ì3.1.5.3.
	*   Any unprintable character is converted to a question mark ("?"),
	*   as is customary. This helps with filtering out noisy strings.
	*/
	void makePrintable(char* str);

	/*
	* Description:
	*   Switches endianness of the given value around. Si4735 is a
	*   big-endian machine while Arduino is little-endian --  a storm of
	*   problems are headed our way if we ignore that.
	* Parameters:
	*   value - the word to be switched
	*/
	inline word switchEndian(word value) { return (value >> 8) | (value << 8); }
};

class Si4737Translate
{
public:
	/*
	* Description:
	*   Translates the given PTY into human-readable text for the given
	*   locale. At most textsize-1 characters will be copied to the buffer
	*   at text.
	*/
	void getTextForPTY(byte PTY, byte locale, char* text, byte textsize);

	/*
	* Description:
	*   Translates the given PTY between the given locales.
	*/
	byte translatePTY(byte PTY, byte fromlocale, byte tolocale);

	/*
	* Description:
	*   Decodes the station callsign out of the PI using the method
	*   defined in the RDBS standard for North America.
	* Parameters:
	*   programIdentifier - a word containing the Program Identifier value
	*                       from RDS
	*   callSign - pointer to a char[] at least 5 characters long that
	*              receives the decoded station call sign
	*/
	void decodeCallSign(word programIdentifier, char* callSign);
};


class Si4737
{
public:
	/*
	* Description:
	*   This the constructor. It assumes SparkFun Si4735 Shield + level
	*   shifter (or the diode fix, or 3.3V-native Arduino) semantics if
	*   called without parameters.
	*   If you're not using the Shield (e.g. using the Breakout Board) or
	*   have wired the Si4735 differently, then explicitly supply the
	*   constructor with the actual pin numbers.
	*   Use the hardwired pins constants above to tell the constructor you
	*   haven't used (and hardwired) some of the pins.
	* Parameters:
	*   interface - interface and protocol used to talk to the chip
	*   pin*      - pin numbers for connections to the Si4735, with
	*               defaults for the SparkFun Si4735 Shield already
	*               provided.
	*/
	Si4737(byte partNumberLastTwo = 37, byte interface = SI4735_INTERFACE_I2C,
		byte pinPower = SI4735_PIN_POWER,
		byte pinReset = SI4735_PIN_RESET,
		byte pinGPO2 = SI4735_PIN_GPO2, byte pinSEN = SI4735_PIN_SEN);

	/*
	* Description:
	*   This is the destructor, it shuts the Si4735 down
	*/
	~Si4737() { end(true); };

	/*
	* Description:
	*   Powers down the radio.
	* Parameters:
	*   hardoff - physically power down the chip if fed off a digital pin,
	*             otherwise just send SI4735_CMD_POWER_DOWN.
	*/
	void end(bool hardoff = false);

	/*
	* Description:
	*   Initializes the Si4735, powers up the radio in the desired mode
	*   and limits the bandwidth appropriately.
	*   This function must be called before any other radio command.
	*   The band limits are set as follows:
	*     AM - 520 to 1710 kHz
	*     FM - 87.5 to 107.9 MHz
	*	  WB - God knows
	* Parameters:
	*   mode        - The desired radio mode, one of the SI4735_MODE_*
	*                 constants.
	*   xosc        - A 32768Hz external oscillator is present.
	*   slowshifter - A BOB-08745 is used for level shifting between an
	*                 Uno/Mega and the Si4735. Use a 3.3V I/O Arduino or
	*                 shift through a BOB-10403 to be able to go up to
	*                 1MHz by setting this to false.
	*/
	void begin(byte mode, bool xosc = true, bool slowshifter = true);

        // Check response of GET_REV command against indicated part number
        void authenticate();

	/*
	* Description:
	*   Used to send a command and its arguments to the radio chip.
	* Parameters:
	*   command - the command byte, see datasheet and use one of the
	SI4735_CMD_* constants
	*   arg1-7  - command arguments, see the Si4735 Programmers Guide.
	*/
	void sendCommand(byte command, byte arg1 = 0, byte arg2 = 0,
		byte arg3 = 0, byte arg4 = 0, byte arg5 = 0,
		byte arg6 = 0, byte arg7 = 0);		

	/*
	* Description:
	*   Gets the current status (short read) of the radio. Learn more
	*   about the status byte in the Si4735 Datasheet.
	* Returns:
	*   The status of the radio.
	*/
	byte getStatus(void);       

	/*
	* Description:
	*   Gets the long response (long read) from the radio. Learn more
	*   about the long response in the Si4735 Datasheet.
	* Parameters:
	*   response - A byte[] at least 16 bytes long for the response from
	*              the radio to be stored in.
	*/
	void getResponse(byte* response);

	/*
	* Description:
	*   Sets a property value, see the SI4735_PROP_* constants and the
	*   Si4735 Datasheet for more information.
	*/
	void setProperty(word property, word value);

	/*
	* Description:
	*   Sets the Mode of the radio.
	* Parameters:
	*   mode      - the new mode of operation (see SI4735_MODE_*).
	*   powerdown - power the chip down first, as required by datasheet.
	*   xosc      - an external 32768Hz oscillator is present.
	*/
	void setMode(byte mode, bool powerdown = true,
		bool xosc = true);

        char getMode();

	/*
	* Description:
	*   Sets deemphasis time constant (see SI4735_FLG_DEEMPH_*).
	*/
	void setDeemphasis(byte deemph);

	/*
	* Description:
	*   Sets stereo/mono
	*/
	void setAudioModeStereo(bool isStereo);

	/*
	* Description:
	*   Unmutes the audio output.
	* Parameters:
	*   minvol - set the volume to minimum value before unmuting if true,
	*            otherwise leave it untouched causing the chip to blast
	*            audio out at whatever the previous volume level was.
	*/
	void unMute(bool minvol = false);

        // Sets AM channel filter parameters.
        void setAmChannelFilter(byte bandwidthSetting, bool powerLineNoiseRejectionEnabled);

	/*
	* Description:
	*   If in FM mode and the chip has received any RDS block, fetch it
	*   off the chip and fill word block[4] with it, returning true;
	*   otherwise return false without side-effects.
	*   This function needs to be actively called (e.g. from loop()) in
	*   order to see sensible information.
	*/
	bool readRDSBlock(word* block);

	/*
	* Description:
	*   Returns true if at least one RDS group has been received while
	*   tuned into the current station.
	*/
	bool getRDSStat(void);

	/*
	* Description:
	*   Retrieves the Received Signal Quality metrics using a
	*   Si4735_RX_Metrics struct.
	*/
	void getRSQ(Si4737_RX_Metrics* RSQ);

	/*
	* Description:
	*   Sets the volume. Valid values are [0-63].
	*/
	void setVolume(int value) {
		setProperty(SI4735_PROP_RX_VOLUME,
			word(0x00, constrain(value, 0, 63)));
	};

	/*
	* Description:
	*   Used to to tune the radio to a desired frequency. The library uses
	*   the mode indicated via begin() to determine how to set the
	*   frequency.
	* Parameters:
	*   frequency - The frequency to tune to
	In kHz for AM
	In 10kHz for FM and WB
	*/
	void setFrequency(long frequency);


	/*
	* Description:
	*   Gets the frequency the chip is currently tuned to.
	* Parameters:
	*   valid - will be set to true if the chip currently detects a valid
	*           (as defined by current Seek/Tune criteria, see
	*           FM_SEEK_TUNE_* properties in the datasheet) signal on this
	*           frequency. Omit if you don't care.
	*/
	word getFrequency(bool* valid = NULL);

	/*
	* Description:
	*   Gets a property value, see the SI4735_PROP_* constants and the
	*   Si4735 Datasheet for more information.
	* Returns:
	*   The current value of property.
	*/
	word getProperty(word property);

	/*
	* Description:
	*   Commands the radio to seek up to the next valid channel. No seek for WB. 
	* Parameters:
	*   wrap - set to true to allow the seek to wrap around the current
	*          band.
	*/
	void seekUp(bool wrap = true);

	/*
	* Description:
	*   Commands the radio to seek down to the next valid channel. No seek for WB. 
	* Parameters:
	*   wrap - set to true to allow the seek to wrap around the current
	*          band.
	*/
	void seekDown(bool wrap = true);


private:
	byte _pinPower, _pinReset, _pinGPO2, _pinSDIO, _pinGPO1, _pinSCLK,
		_pinSEN;
	byte _partNumberLastTwo, _mode, _response[16], _i2caddr;
	bool _haverds;

	/*
	* Description:
	*   Enables RDS reception.
	*/
	void enableRDS(void);

	/*
	* Description:
	*   Waits for completion of various operations.
	* Parameters:
	*   which - interrupt flag to wait for, see SI4735_STATUS_*
	*/
	void waitForInterrupt(byte which);

	/*
	* Description:
	*   Performs actions common to all tuning modes.
	*/
	void completeTune(void);
};

#endif