ADS7828 Class Reference

Collaboration diagram for ADS7828:

Public Member Functions
	ADS7828 (uint8_t)
	Constructor with the following defaults: More...
	ADS7828 (uint8_t, uint8_t)
	ADS7828 (uint8_t, uint8_t, uint8_t)
	ADS7828 (uint8_t, uint8_t, uint8_t, uint16_t, uint16_t)
uint8_t	address ()
	Device address as defined by pins A1, A0. More...
ADS7828Channel *	channel (uint8_t)
	Return pointer to channel object. More...
uint8_t	commandByte ()
	Return command byte for device object (PD1 PD0 bits only). More...
uint8_t	start ()
	Initiate communication with device. More...
uint8_t	start (uint8_t)
uint8_t	update ()
	Update all unmasked channels on device. More...
uint8_t	update (uint8_t)

Static Public Member Functions
static void	begin ()
	Enable I2C communication. More...
static ADS7828 *	device (uint8_t)
	Return pointer to device object. More...
static uint8_t	updateAll ()
	Update all unmasked channels on all registered devices. More...

Public Attributes
uint8_t	channelMask
	Each bit position containing a 1 represents a channel that is to be read via update() / updateAll(). More...

Private Member Functions
void	init (uint8_t, uint8_t, uint8_t, uint16_t, uint16_t)
	Common code for constructors. More...
uint16_t	read ()
	Request and receive data from most-recent A/D conversion from device. More...

Static Private Member Functions
static uint16_t	read (uint8_t)
	Request and receive data from most-recent A/D conversion from device. More...
static uint8_t	start (uint8_t, uint8_t)
	Initiate communication with device. More...
static uint8_t	update (ADS7828 *)
	Initiate communication with device. More...
static uint8_t	update (ADS7828 *, uint8_t)
	Initiate communication with device. More...

Private Attributes
uint8_t	address_
	Device address as defined by pins A1, A0.
ADS7828Channel	channels_ [8]
	Array of channel objects.
uint8_t	commandByte_
	Command byte for device object (PD1 PD0 bits only).

Static Private Attributes
static ADS7828 *	devices_ [4] = {}
	Array of pointers to registered device objects.
static const uint8_t	BASE_ADDRESS_ = 0x48
	Factory pre-set slave address.

Related Functions
(Note that these are not member functions.)
static const uint8_t	DIFFERENTIAL = 0 << 7
	Configure channels to use differential inputs (Command byte SD=0). More...
static const uint8_t	SINGLE_ENDED = 1 << 7
	Configure channels to use single-ended inputs (Command byte SD=1). More...
static const uint8_t	REFERENCE_OFF = 0 << 3
	Configure channels to turn internal reference OFF between conversions (Command byte PD1=0). More...
static const uint8_t	REFERENCE_ON = 1 << 3
	Configure channels to turn internal reference ON between conversions (Command byte PD1=1). More...
static const uint8_t	ADC_OFF = 0 << 2
	Configure channels to turn A/D converter OFF between conversions (Command byte PD0=0). More...
static const uint8_t	ADC_ON = 1 << 2
	Configure channels to turn A/D converter ON between conversions (Command byte PD0=1). More...
static const uint8_t	DEFAULT_CHANNEL_MASK = 0xFF
	Default channel mask used in ADS7828 constructor.
static const uint16_t	DEFAULT_MIN_SCALE = 0
	Default scaling minimum value used in ADS7828 constructor.
static const uint16_t	DEFAULT_MAX_SCALE = 0xFFF
	Default scaling maximum value used in ADS7828 constructor.

Detailed Description

Examples:

examples/one_device/one_device.ino, and examples/two_devices/two_devices.ino.

Constructor & Destructor Documentation

ADS7828() [1/4]

ADS7828::ADS7828

(

uint8_t

address

)

Constructor with the following defaults:

• differential inputs (SD=0)
• internal reference OFF between conversions (PD1=0)
• A/D converter OFF between conversions (PD0=0)
• min scale=0
• max scale=4095

Parameters

address

device address (0..3)

Usage:

...
// construct device with address 2
ADS7828 adc(2);
...

See also

ADS7828::address()

{
  init(address, (DIFFERENTIAL | REFERENCE_OFF | ADC_OFF),
    DEFAULT_CHANNEL_MASK, DEFAULT_MIN_SCALE, DEFAULT_MAX_SCALE);
}

ADS7828() [2/4]

ADS7828::ADS7828	(	uint8_t	address,
		uint8_t	options
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

options

command byte bits SD, PD1, PD0

Usage:

...
// device address 0, differential inputs, ref/ADC ON between conversions
ADS7828 adc0(0, DIFFERENTIAL | REFERENCE_ON | ADC_ON);

// device address 1, single-ended inputs, ref/ADC OFF between conversions
ADS7828 adc1(1, SINGLE_ENDED | REFERENCE_OFF | ADC_OFF);

// device address 2, single-ended inputs, ref/ADC ON between conversions
ADS7828 adc2(2, SINGLE_ENDED | REFERENCE_ON | ADC_ON);
...

See also

ADS7828Channel::commandByte()

{
  init(address, options, DEFAULT_CHANNEL_MASK, DEFAULT_MIN_SCALE,
    DEFAULT_MAX_SCALE);
}

ADS7828() [3/4]

ADS7828::ADS7828	(	uint8_t	address,
		uint8_t	options,
		uint8_t	channelMask
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

channelMask

bit positions containing a 1 represent channels that are to be read via update() / updateAll()

Usage:

...
// device address 0, update all channels via updateAll() (bits 7..0 are set)
ADS7828 adc0(0, 0, 0xFF);

// device address 1, update channels 0..3 via updateAll() (bits 3..0 are set)
ADS7828 adc1(1, 0, 0b00001111);

// device address 2, update channels 0, 1, 2, 7 via updateAll() (bits 7, 2, 1, 0 are set)
ADS7828 adc2(2, 0, 0b10000111);
...

See also

ADS7828::channelMask

{
  init(address, options, channelMask, DEFAULT_MIN_SCALE, DEFAULT_MAX_SCALE);
}

ADS7828() [4/4]

ADS7828::ADS7828	(	uint8_t	address,
		uint8_t	options,
		uint8_t	channelMask,
		uint16_t	min,
		uint16_t	max
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

min	minimum scaling value applied to value()
max	maximum scaling value applied to value()

Usage:

...
// device address 2, channel default minScale 0, maxScale 100
ADS7828 adc(2, 0, DEFAULT_CHANNEL_MASK, 0, 100);
...

See also

ADS7828Channel::minScale, ADS7828Channel::maxScale

{
  init(address, options, channelMask, min, max);
}

Member Function Documentation

address()

uint8_t ADS7828::address

(

)

Device address as defined by pins A1, A0.

Return values

0x00	A1=0, A0=0
0x01	A1=0, A0=1
0x02	A1=1, A0=0
0x03	A1=1, A0=1

Usage:

...
ADS7828 adc(3);
uint8_t deviceAddress = adc.address();
...

Examples:

examples/two_devices/two_devices.ino.

{
  return address_;
}

channel()

ADS7828Channel * ADS7828::channel

(

uint8_t

ch

)

Return pointer to channel object.

Parameters

ch	channel number (0..7)

Returns

pointer to ADS7828Channel object

Usage:

...
ADS7828 adc(0);
ADS7828Channel* temperature = adc.channel(0);
...

Examples:

examples/one_device/one_device.ino.

{
  return &channels_[ch & 0x07];
}

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commandByte()

uint8_t ADS7828::commandByte

(

)

Return command byte for device object (PD1 PD0 bits only).

Optional Function (Troubleshooting):

This function is for testing and troubleshooting.

Return values

0x00	Power Down Between A/D Converter Conversions
0x04	Internal Reference OFF and A/D Converter ON
0x08	Internal Reference ON and A/D Converter OFF
0x0C	Internal Reference ON and A/D Converter ON

Usage:

...
ADS7828 adc(0);
uint8_t command = adc.commandByte();
...

{
  return commandByte_;
}

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start() [1/3]

uint8_t ADS7828::start

(

)

Initiate communication with device.

Optional Function (Troubleshooting):

This function is for testing and troubleshooting and can be used to determine whether a device is available (similar to the TCP/IP ping command).

Return values

0	success
1	length too long for buffer
2	address send, NACK received (device not on bus)
3	data send, NACK received
4	other twi error (lost bus arbitration, bus error, ...)

Usage:

...
ADS7828 adc(3);
// test whether device is available
uint8_t status = adc.start();
...

{
  return start(0);
}

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start() [2/3]

uint8_t ADS7828::start

(

uint8_t

ch

)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Optional Function (Troubleshooting):

This function is for testing and troubleshooting.

Parameters

ch	channel number (0..7)

Return values

0	success
1	length too long for buffer
2	address send, NACK received (device not on bus)
3	data send, NACK received
4	other twi error (lost bus arbitration, bus error, ...)

Usage:

...
ADS7828 adc(0);
// test whether device is available (channel 3 A/D conversion started)
uint8_t status = adc.start(3);
...

{
  return start(address_, commandByte_ | channel(ch)->commandByte());
}

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update() [1/4]

uint8_t ADS7828::update

(

)

Update all unmasked channels on device.

Required Function:

Call this or one of the update() / updateAll() functions from within loop() in order to read data from device(s).

Returns

quantity of channels updated (0..8)

Usage:

...
ADS7828 adc(0);
...
void loop()
{
  ...
  // update device 0, all unmasked channels
  uint8_t quantity = adc.update();
  ...
}
...

{
  return update(this);
}

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update() [2/4]

uint8_t ADS7828::update

(

uint8_t

ch

)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Required Function:

Call this or one of the update() / updateAll() functions from within loop() in order to read data from device(s).

Parameters

ch	channel number (0..7)

Return values

0	success
1	length too long for buffer
2	address send, NACK received (device not on bus)
3	data send, NACK received
4	other twi error (lost bus arbitration, bus error, ...)

Usage:

...
ADS7828 adc(0);
...
void loop()
{
  ...
  // update device 0, channel 3
  uint8_t status = adc.update(3);
  ...
}
...

{
  return update(this, ch);
}

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begin()

void ADS7828::begin ( )

static

Enable I2C communication.

Required Function:

Call from within setup()to enable I2C communication.

Usage:

...
void setup()
{
  // enable I2C communication
  ADS7828::begin();
}
...

Examples:

examples/one_device/one_device.ino, and examples/two_devices/two_devices.ino.

{
  Wire.begin();
}

device()

ADS7828 * ADS7828::device ( uint8_t  address )

static

Return pointer to device object.

Parameters

address

device address (0..3)

Returns

pointer to ADS7828 object

Usage:

...
// device 2 pointer
ADS7828* device2 = ADS7828::device(2);
...

Examples:

examples/two_devices/two_devices.ino.

{
  return devices_[address & 0x03];
}

updateAll()

uint8_t ADS7828::updateAll ( )

static

Update all unmasked channels on all registered devices.

Required Function:

Call this or one of the update() functions from within loop() in order to read data from device(s). This is the most commonly-used device update function.

Returns

quantity of channels updated (0..32)

Usage:

...
void loop()
{
  ...
  // update all registered ADS7828 devices/unmasked channels
  uint8_t quantity = ADS7828::updateAll();
  ...
}
...

Examples:

examples/one_device/one_device.ino, and examples/two_devices/two_devices.ino.

{
  uint8_t a, ch, count = 0;
  for (a = 0; a < 4; a++)
  {
    if (0 != devices_[a]) count += update(devices_[a]);
  }
  return count;
}

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init()

void ADS7828::init ( uint8_t  address, uint8_t  options, uint8_t  channelMask, uint16_t  min, uint16_t  max  )

private

Common code for constructors.

Parameters

address	device address (0..3)
options	command byte bits SD, PD1, PD0
channelMask	bit positions containing a 1 represent channels that are to be read via update() / updateAll()
min	minimum scaling value applied to value()
max	maximum scaling value applied to value()

{
  this->address_ = address & 0x03;     // A1 A0 bits
  this->commandByte_ = options & 0x0C; // PD1 PD0 bits
  this->channelMask = channelMask;
  for (uint8_t ch = 0; ch < 8; ch++)
  {
    channels_[ch] = ADS7828Channel(this, ch, options, min, max);
  }
  this->devices_[address_] = this;
}

read() [1/2]

uint16_t ADS7828::read ( )

private

Request and receive data from most-recent A/D conversion from device.

Returns

16-bit zero-padded word (12 data bits D11..D0)

{
  return read(address_);
}

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read() [2/2]

uint16_t ADS7828::read ( uint8_t  address )

staticprivate

Request and receive data from most-recent A/D conversion from device.

Parameters

address

device address (0..3)

Returns

16-bit zero-padded word (12 data bits D11..D0)

{
  Wire.requestFrom(BASE_ADDRESS_ | (address & 0x03), 2);
  return word(Wire.read(), Wire.read());
}

start() [3/3]

uint8_t ADS7828::start ( uint8_t  address, uint8_t  command  )

staticprivate

Initiate communication with device.

Parameters

address	device address (0..3)
command	command byte (0x00..0xFC)

Return values

0	success
1	length too long for buffer
2	address send, NACK received (device not on bus)
3	data send, NACK received
4	other twi error (lost bus arbitration, bus error, ...)

{
  Wire.beginTransmission(BASE_ADDRESS_ | (address & 0x03));
  Wire.write((uint8_t) command);
  return Wire.endTransmission();
}

update() [3/4]

uint8_t ADS7828::update ( ADS7828 *  device )

staticprivate

Initiate communication with device.

Parameters

device

pointer to device object

Returns

quantity of channels updated (0..8)

{
  if (0 == device) device = devices_[0];
  uint8_t ch, count = 0;
  for (ch = 0; ch < 8; ch++)
  {
    if (bitRead(device->channelMask, ch))
    {
      if (0 == update(device, ch)) count++;
    }
  }
  return count;
}

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update() [4/4]

uint8_t ADS7828::update ( ADS7828 *  device, uint8_t  ch  )

staticprivate

Initiate communication with device.

Parameters

device	pointer to device object
ch	channel number (0..7)

Return values

0	success
1	length too long for buffer
2	address send, NACK received (device not on bus)
3	data send, NACK received
4	other twi error (lost bus arbitration, bus error, ...)

{
  if (0 == device) device = devices_[0];
  uint8_t status = device->start(ch);
  if (0 == status) device->channel(ch)->newSample(device->read());
  return status;
}

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Friends And Related Function Documentation

DIFFERENTIAL

const uint8_t DIFFERENTIAL = 0 << 7

related

Configure channels to use differential inputs (Command byte SD=0).

Use either DIFFERENTIAL or SINGLE_ENDED in ADS7828 constructor; default is DIFFERENTIAL.

Usage:

...
// address 0, differential inputs, ref/ADC OFF between conversions
ADS7828 adc0(0, DIFFERENTIAL | REFERENCE_OFF | ADC_OFF);
...

SINGLE_ENDED

const uint8_t SINGLE_ENDED = 1 << 7

related

Configure channels to use single-ended inputs (Command byte SD=1).

Use either DIFFERENTIAL or SINGLE_ENDED in ADS7828 constructor; default is DIFFERENTIAL.

Usage:

...
// address 1, single-ended inputs, ref/ADC OFF between conversions
ADS7828 adc1(1, SINGLE_ENDED | REFERENCE_OFF | ADC_OFF);
...

Examples:

examples/one_device/one_device.ino, and examples/two_devices/two_devices.ino.

REFERENCE_OFF

const uint8_t REFERENCE_OFF = 0 << 3

related

Configure channels to turn internal reference OFF between conversions (Command byte PD1=0).

Use either REFERENCE_OFF or REFERENCE_ON in ADS7828 constructor; default is REFERENCE_OFF.

Usage:

...
// address 0, differential inputs, ref/ADC OFF between conversions
ADS7828 adc0(0, DIFFERENTIAL | REFERENCE_OFF | ADC_OFF);
...

REFERENCE_ON

const uint8_t REFERENCE_ON = 1 << 3

related

Configure channels to turn internal reference ON between conversions (Command byte PD1=1).

Use either REFERENCE_OFF or REFERENCE_ON in ADS7828 constructor; default is REFERENCE_OFF.

Usage:

...
// address 2, differential inputs, ref ON/ADC OFF between conversions
ADS7828 adc2(2, DIFFERENTIAL | REFERENCE_ON | ADC_OFF);
...

Examples:

examples/one_device/one_device.ino, and examples/two_devices/two_devices.ino.

ADC_OFF

const uint8_t ADC_OFF = 0 << 2

related

Configure channels to turn A/D converter OFF between conversions (Command byte PD0=0).

Use either ADC_OFF or ADC_ON in ADS7828 constructor; default is ADC_OFF.

Usage:

...
// address 0, differential inputs, ref/ADC OFF between conversions
ADS7828 adc0(0, DIFFERENTIAL | REFERENCE_OFF | ADC_OFF);
...

ADC_ON

const uint8_t ADC_ON = 1 << 2

related

Configure channels to turn A/D converter ON between conversions (Command byte PD0=1).

Use either ADC_OFF or ADC_ON in ADS7828 constructor; default is ADC_OFF.

Usage:

...
// address 3 , differential inputs, ref OFF/ADC ON between conversions
ADS7828 adc3(3, DIFFERENTIAL | REFERENCE_OFF | ADC_ON);
...

Examples:

examples/one_device/one_device.ino, and examples/two_devices/two_devices.ino.

Member Data Documentation

channelMask

uint8_t ADS7828::channelMask

Each bit position containing a 1 represents a channel that is to be read via update() / updateAll().

---

The documentation for this class was generated from the following files:

• i2c_adc_ads7828.h
• i2c_adc_ads7828.cpp