AD9954 DDS (Direct Digital Synthesizer)

Functions to control the Analog Devices AD9954 DDS. More...

Defines

#define DDS_AD9954_CFR1   0x00

AD9954 CFR1 - Control functions including RAM, profiles, OSK, sync, sweep, SPI, and power control settings.

#define DDS_AD9954_CFR2   0x01

AD9954 CFR2 - Control functions including sync, PLL multiplier, VCO range, and charge pump current.

#define DDS_AD9954_ASF   0x02

AD9954 ASF - Auto ramp rate speed control and output scale factor (0x0000 to 0x3fff).

#define DDS_AD9954_ARR   0x03

AD9954 ARR - Amplitude ramp rate for OSK function.

#define DDS_AD9954_FTW0   0x04

AD9954 FTW0 - Frequency tuning word 0.

#define DDS_AD9954_FTW1   0x06

AD9954 FTW1 - Frequency tuning word 1.

#define DDS_AD9954_NLSCW   0x07

AD9954 NLSCW - Negative Linear Sweep Control Word used for spectral shaping in FSK mode.

#define DDS_AD9954_PLSCW   0x08

AD9954 PLSCW - Positive Linear Sweep Control Word used for spectral shaping in FSK mode.

#define DDS_AD9954_RWCW0   0x07

AD9954 RSCW0 - RAM Segment Control Word 0.

#define DDS_AD9954_RWCW1   0x08

AD9954 RSCW0 - RAM Segment Control Word 1.

#define DDS_RAM   0x0b

AD9954 RAM segment.

#define DDS_FREQ_TO_FTW_DIGITS   9

Number of digits in DDS frequency to FTW conversion.

Functions

void ddsInit ()

Initialize the DDS regsiters and RAM.

void ddsSetOutputScale (uint16_t scale)

Set DDS amplitude value in the range 0 to 16383 where 16383 is full scale.

void ddsSetAmplitude (uint8_t amplitude)

Set the DDS amplitude in units of dBc of full scale where 1 is 0.1 dB.

void ddsSetFreq (uint32_t freq)

Convert frequency in hertz to 32-bit DDS FTW (Frequency Tune Word).

void ddsPhase (bool_t phase)

Set the output phase.

void ddsPTT (bool_t state)

Turn on the DDS output.

void ddsSetFTW (uint32_t ftw)

Set DDS frequency tuning word.

void ddsSetMode (DDS_MODE mode)

Set the DDS to run in A-FSK, FSK, or PSK31 mode.

Variables

const uint32_t DDS_MULT [DDS_FREQ_TO_FTW_DIGITS] = { 11, 1, 8, 4, 8, 1, 0, 6, 6 }

Array of multiplication factors used to convert frequency to the FTW.

const uint32_t DDS_DIVISOR [DDS_FREQ_TO_FTW_DIGITS-1] = { 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000 }

Array of divisors used to convert frequency to the FTW.

const uint16_t DDS_AMP_TO_SCALE []

Lookup table to convert dB amplitude scale in 0.5 steps to a linear DDS scale factor.

const uint32_t freqTable [256]

Detailed Description

Functions to control the Analog Devices AD9954 DDS.

Define Documentation

#define DDS_AD9954_ARR 0x03

AD9954 ARR - Amplitude ramp rate for OSK function.

Referenced by ddsInit().

#define DDS_AD9954_ASF 0x02

AD9954 ASF - Auto ramp rate speed control and output scale factor (0x0000 to 0x3fff).

Referenced by ddsSetOutputScale().

#define DDS_AD9954_CFR1 0x00

AD9954 CFR1 - Control functions including RAM, profiles, OSK, sync, sweep, SPI, and power control settings.

Referenced by ddsSetMode().

#define DDS_AD9954_CFR2 0x01

AD9954 CFR2 - Control functions including sync, PLL multiplier, VCO range, and charge pump current.

#define DDS_AD9954_FTW0 0x04

AD9954 FTW0 - Frequency tuning word 0.

Referenced by ddsSetFTW().

#define DDS_AD9954_FTW1 0x06

AD9954 FTW1 - Frequency tuning word 1.

#define DDS_AD9954_NLSCW 0x07

AD9954 NLSCW - Negative Linear Sweep Control Word used for spectral shaping in FSK mode.

Referenced by ddsSetMode().

#define DDS_AD9954_PLSCW 0x08

AD9954 PLSCW - Positive Linear Sweep Control Word used for spectral shaping in FSK mode.

Referenced by ddsSetMode().

#define DDS_AD9954_RWCW0 0x07

AD9954 RSCW0 - RAM Segment Control Word 0.

#define DDS_AD9954_RWCW1 0x08

AD9954 RSCW0 - RAM Segment Control Word 1.

#define DDS_FREQ_TO_FTW_DIGITS 9

Number of digits in DDS frequency to FTW conversion.

Referenced by ddsSetFreq().

#define DDS_RAM 0x0b

AD9954 RAM segment.

Function Documentation

void ddsInit ( )

Initialize the DDS regsiters and RAM.

References DDS_AD9954_ARR, DDS_MODE_POWERDOWN, ddsSetMode(), ddsSetOutputScale(), IO_CS, IO_OSK, IO_PS0, IO_PS1, and IO_UPDATE.

Referenced by main().

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void ddsPhase ( bool_t phase )

Set the output phase.

Parameters:

phase

true for 180 degree phase shift; false for 0 degree phase shift

References IO_CS, and IO_UPDATE.

Referenced by diagPort(), and psk31TimeUpdate().

void ddsPTT ( bool_t state ) [inline]

Turn on the DDS output.

Parameters:

state

true to activate; otherwise false

References IO_OSK.

Referenced by tncTimeUpdate(), and tncTxPacket().

void ddsSetAmplitude ( uint8_t amplitude )

Set the DDS amplitude in units of dBc of full scale where 1 is 0.1 dB.

For example, a value of 30 is 3dBc or a value of 85 is 8.5dBc.

Parameters:

amplitude

in 0.1 dBc of full scale

References DDS_AMP_TO_SCALE, ddsSetOutputScale(), and IO_OSK.

Referenced by diagPort(), psk31TxPacket(), and tncTxPacket().

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void ddsSetFreq ( uint32_t freq )

Convert frequency in hertz to 32-bit DDS FTW (Frequency Tune Word).

Parameters:

freq

frequency in Hertz

References DDS_DIVISOR, DDS_FREQ_TO_FTW_DIGITS, DDS_MULT, and ddsSetFTW().

Referenced by diagPort(), and psk31TxPacket().

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void ddsSetFTW ( uint32_t ftw )

Set DDS frequency tuning word.

The output frequency is equal to RefClock * (ftw / 2 ^ 32).

Parameters:

ftw

Frequency Tuning Word

References DDS_AD9954_FTW0, IO_CS, and IO_UPDATE.

Referenced by ddsSetFreq(), and tncTimeUpdate().

void ddsSetMode ( DDS_MODE mode )

Set the DDS to run in A-FSK, FSK, or PSK31 mode.

Parameters:

mode

DDS_MODE_APRS, DDS_MODE_PSK31, or DDS_MODE_HF_APRS constant

References DDS_AD9954_CFR1, DDS_AD9954_NLSCW, DDS_AD9954_PLSCW, DDS_MODE_APRS, DDS_MODE_HF_APRS, DDS_MODE_POWERDOWN, DDS_MODE_PSK31, IO_CS, and IO_UPDATE.

Referenced by ddsInit(), diagPort(), psk31TimeUpdate(), psk31TxPacket(), tncTimeUpdate(), and tncTxPacket().

void ddsSetOutputScale ( uint16_t scale )

Set DDS amplitude value in the range 0 to 16383 where 16383 is full scale.

This value is a linear multiplier and needs to be scale for RF output power in log scale.

Parameters:

scale

in the range 0 to 16383

References DDS_AD9954_ASF, IO_CS, and IO_UPDATE.

Referenced by ddsInit(), and ddsSetAmplitude().

Variable Documentation

const uint16_t DDS_AMP_TO_SCALE[]

Initial value:

 { 16383, 15467, 14601, 13785,  13013, 12286, 11598, 10949,  10337, 9759, 9213, 8697, 
8211, 7752, 7318, 6909,  6522, 6157, 5813, 5488,  5181, 4891, 4617, 4359,  4115, 3885, 3668, 3463, 
3269, 3086, 2913, 2750,  2597, 2451, 2314, 2185,  2062, 1947, 1838, 1735,  1638 }

Lookup table to convert dB amplitude scale in 0.5 steps to a linear DDS scale factor.

Referenced by ddsSetAmplitude().

const uint32_t DDS_DIVISOR[DDS_FREQ_TO_FTW_DIGITS-1] = { 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000 }

Array of divisors used to convert frequency to the FTW.

Referenced by ddsSetFreq().

const uint32_t DDS_MULT[DDS_FREQ_TO_FTW_DIGITS] = { 11, 1, 8, 4, 8, 1, 0, 6, 6 }

Array of multiplication factors used to convert frequency to the FTW.

Referenced by ddsSetFreq().

const uint32_t freqTable[256]

Referenced by tncTimeUpdate().


Defines
#define	DDS_AD9954_CFR1 0x00
	AD9954 CFR1 - Control functions including RAM, profiles, OSK, sync, sweep, SPI, and power control settings.
#define	DDS_AD9954_CFR2 0x01
	AD9954 CFR2 - Control functions including sync, PLL multiplier, VCO range, and charge pump current.
#define	DDS_AD9954_ASF 0x02
	AD9954 ASF - Auto ramp rate speed control and output scale factor (0x0000 to 0x3fff).
#define	DDS_AD9954_ARR 0x03
	AD9954 ARR - Amplitude ramp rate for OSK function.
#define	DDS_AD9954_FTW0 0x04
	AD9954 FTW0 - Frequency tuning word 0.
#define	DDS_AD9954_FTW1 0x06
	AD9954 FTW1 - Frequency tuning word 1.
#define	DDS_AD9954_NLSCW 0x07
	AD9954 NLSCW - Negative Linear Sweep Control Word used for spectral shaping in FSK mode.
#define	DDS_AD9954_PLSCW 0x08
	AD9954 PLSCW - Positive Linear Sweep Control Word used for spectral shaping in FSK mode.
#define	DDS_AD9954_RWCW0 0x07
	AD9954 RSCW0 - RAM Segment Control Word 0.
#define	DDS_AD9954_RWCW1 0x08
	AD9954 RSCW0 - RAM Segment Control Word 1.
#define	DDS_RAM 0x0b
	AD9954 RAM segment.
#define	DDS_FREQ_TO_FTW_DIGITS 9
	Number of digits in DDS frequency to FTW conversion.
Functions
void	ddsInit ()
	Initialize the DDS regsiters and RAM.
void	ddsSetOutputScale (uint16_t scale)
	Set DDS amplitude value in the range 0 to 16383 where 16383 is full scale.
void	ddsSetAmplitude (uint8_t amplitude)
	Set the DDS amplitude in units of dBc of full scale where 1 is 0.1 dB.
void	ddsSetFreq (uint32_t freq)
	Convert frequency in hertz to 32-bit DDS FTW (Frequency Tune Word).
void	ddsPhase (bool_t phase)
	Set the output phase.
void	ddsPTT (bool_t state)
	Turn on the DDS output.
void	ddsSetFTW (uint32_t ftw)
	Set DDS frequency tuning word.
void	ddsSetMode (DDS_MODE mode)
	Set the DDS to run in A-FSK, FSK, or PSK31 mode.
Variables
const uint32_t	DDS_MULT [DDS_FREQ_TO_FTW_DIGITS] = { 11, 1, 8, 4, 8, 1, 0, 6, 6 }
	Array of multiplication factors used to convert frequency to the FTW.
const uint32_t	DDS_DIVISOR [DDS_FREQ_TO_FTW_DIGITS-1] = { 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000 }
	Array of divisors used to convert frequency to the FTW.
const uint16_t	DDS_AMP_TO_SCALE []
	Lookup table to convert dB amplitude scale in 0.5 steps to a linear DDS scale factor.
const uint32_t	freqTable [256]