adc Namespace Reference

Data Structures
struct	Adc
	Singleton instance of the ADC.
struct	AdcFrame
	Private/static data member for use by the ISR.
struct	Channel
	Single ADC channel (pin + metadata). More...
struct	State

Enumerations
enum struct	BitResolution : uint8_t { Eight = 8 , Ten = 10 }
	Supported bit resolutions for ADC sampling. More...
enum struct	AutotriggerSource : uint8_t {   FreeRunning = 0b000 , AnalogComparator = 0b001 , ExternalIrq0 = 0b010 , TimCnt0CmpA = 0b011 ,   TimCnt0Ovf = 0b100 , TimCnt1CmpB = 0b101 , TimCnt1Ovf = 0b110 , TimCnt1Cap = 0b111 }
	Potential sources for ADC interrupts to be triggered by. More...

Functions
	ISR (ADC_vect)
	Interrupt service routine responsible for reading samples from the ADC.
int8_t	drain_buffer (uint8_t **buf, size_t &sz, size_t &ch_index)
	NOT SAFE TO USE WHEN THE ADC IS ENABLED!
int8_t	swap_buffer (uint8_t **buf, size_t &sz, size_t &ch_index)
	Retrieve a buffer from the module belonging to a specific channel, writing the size and channel index to the reference arguments.
bool	init (uint8_t _nchannels, Channel *_channels, uint8_t *_buf, size_t _sz)
	Initialize ADC module with these parameters for sampling.
void	on ()
	Activate internal board's ADC.
void	off ()
	Turn off ADC.
void	sleep ()
	Turn off ADC and enter sleep mode.
int8_t	start (BitResolution res, uint32_t sample_rate, size_t ch_window_sz=1, uint32_t warmup_ms=100)
	Start ADC sampling at a certain rate with a given bit resolution.
uint32_t	collected ()
uint32_t	stop ()
	Stops ADC sampling and performs cleanup on registers.
size_t	bytes_per_sample (BitResolution res)

Variables
const size_t	MAX_CHANNEL_COUNT = 16
	Number of channels supported by the ADC (0 - 15).

Enumeration Type Documentation

AutotriggerSource

enum struct adc::AutotriggerSource : uint8_t

strong

Potential sources for ADC interrupts to be triggered by.

Maps to the bit patterns used to set source in ADCSRB register.

Enumerator
FreeRunning	0b000
AnalogComparator	0b001
ExternalIrq0	0b010
TimCnt0CmpA	0b011
TimCnt0Ovf	0b100
TimCnt1CmpB	0b101
TimCnt1Ovf	0b110
TimCnt1Cap	0b111

BitResolution

enum struct adc::BitResolution : uint8_t

strong

Supported bit resolutions for ADC sampling.

Enumerator
Eight
Ten

Function Documentation

bytes_per_sample()

size_t adc::bytes_per_sample

(

BitResolution

res

)

collected()

uint32_t adc::collected

(

)

Returns

(uint32_t): Number of samples collected in the current/previous round of sampling.

drain_buffer()

int8_t adc::drain_buffer	(	uint8_t **	buf,
		size_t &	sz,
		size_t &	ch_index
	)

NOT SAFE TO USE WHEN THE ADC IS ENABLED!

Identical API as swap_buffer but this will also give the active buffer. Used to drain any remaining samples from the buffer.

init()

bool adc::init	(	uint8_t	nchannels,
		Channel *	channels,
		uint8_t *	buf,
		size_t	sz
	)

Initialize ADC module with these parameters for sampling.

ISR()

adc::ISR

(

ADC_vect

)

Interrupt service routine responsible for reading samples from the ADC.

off()

void adc::off

(

)

Turn off ADC.

on()

void adc::on

(

)

Activate internal board's ADC.

Wake up from sleep mode.

sleep()

void adc::sleep

(

)

Turn off ADC and enter sleep mode.

start()

int8_t adc::start	(	BitResolution	res,
		uint32_t	sample_rate,
		size_t	ch_window_sz = 1,
		uint32_t	warmup_ms = 100
	)

Start ADC sampling at a certain rate with a given bit resolution.

Parameters

res	Bit resolution to use.
sample_rate	Sample rate in Hz to try and record at,
ch_window_sz	Size of each channel's window. Only checked when there are multiple channels being recorded from. Defaults to 8.
warmup_ms	Milliseconds to delay after starting ADC before ingesting samples. A small warmup helps prevent poor signal from channel switching noise.

Returns

(int8_t): Return code. 0 if all is good, negative otherwise.

stop()

uint32_t adc::stop

(

)

Stops ADC sampling and performs cleanup on registers.

Returns

(uint32_t): Number of samples collected.

swap_buffer()

int8_t adc::swap_buffer	(	uint8_t **	buf,
		size_t &	sz,
		size_t &	ch_index
	)

Retrieve a buffer from the module belonging to a specific channel, writing the size and channel index to the reference arguments.

Intent: Call this in a busy loop starting with a nullptr and write data out to the appropriate channel as it comes in.

Parameters

buf	Pointer to buffer being swapped. If it is a null-pointer, will try to swap it with a currently full buffer without marking it as usable by the ISR. If it is one of the double buffers, will free the buffer for use again and try to exchange it for the other buffer if possible.
sz	Out-parameter for the number of bytes in the buffer.
ch_index	Out-paramter for the channel index this data is from.

Returns

(int8_t): 0 if a new buffer is returned. Nonzero otherwise.

Variable Documentation

MAX_CHANNEL_COUNT

const size_t adc::MAX_CHANNEL_COUNT = 16

Number of channels supported by the ADC (0 - 15).