Low-level ADC peripheral driver interface. More...

Detailed Description

This is a very simple ADC interface to allow platform independent access to a MCU's ADC unit(s). This interface is intentionally designed as simple as possible, to allow for very easy implementation and maximal portability.

As of now, the interface does not allow for any advanced ADC concepts (e.g. continuous mode, scan sequences, injections). It is to be determined, if these features will ever be integrated in this interface, or if it does make more sense to create a second, advanced ADC interface for this.

The ADC driver interface is built around the concept of ADC lines. An ADC line in this context is a tuple consisting out of a hardware ADC device (an ADC functional unit on the MCU) and an ADC channel connected to pin.

If a MCU has more than one hardware ADC unit, the ADC lines can be mapped in a way, that it is possible to sample multiple lines in parallel, given that the ADC implementation allows for interruption of the program flow while waiting for the result of a conversion (e.g. through putting the calling thread to sleep while waiting for the conversion results).

Todo:
Extend interface for continuous mode?

Files

file  adc.h
 Low-level ADC peripheral driver interface definitions.
 

Functions

int adc_init (adc_t line)
 Initialize the given ADC line. More...
 
int adc_sample (adc_t line, adc_res_t res)
 Sample a value from the given ADC line. More...
 
typedef unsigned int adc_t
 Define default ADC type identifier.
 
#define ADC_UNDEF   (UINT_MAX)
 Default ADC undefined value.
 
#define ADC_LINE(x)   (x)
 Default ADC line access macro.
 
enum  adc_res_t {
  ADC_RES_6BIT = (0xa00), ADC_RES_7BIT = (0 << 4), ADC_RES_8BIT = (0xb00), ADC_RES_9BIT = (1 << 4),
  ADC_RES_10BIT = (2 << 4), ADC_RES_12BIT = (3 << 4), ADC_RES_14BIT = (0xc00), ADC_RES_16BIT = (0xd00),
  ADC_RES_6BIT = 0x1, ADC_RES_8BIT = 0x2, ADC_RES_10BIT = ADC_MR_LOWRES_BITS_10, ADC_RES_12BIT = ADC_MR_LOWRES_BITS_12,
  ADC_RES_14BIT = 0x4, ADC_RES_16BIT = 0x8, ADC_RES_6BIT = 0xff, ADC_RES_8BIT = ADC_CTRLB_RESSEL_8BIT,
  ADC_RES_10BIT = ADC_CTRLB_RESSEL_10BIT, ADC_RES_12BIT = ADC_CTRLB_RESSEL_12BIT, ADC_RES_14BIT = 0xfe, ADC_RES_16BIT = 0xfd,
  ADC_RES_6BIT = 0xff, ADC_RES_8BIT = ADC_CTRLC_RESSEL_8BIT, ADC_RES_10BIT = ADC_CTRLC_RESSEL_10BIT, ADC_RES_12BIT = ADC_CTRLC_RESSEL_12BIT,
  ADC_RES_14BIT = 0xfe, ADC_RES_16BIT = 0xfd, ADC_RES_6BIT = 0x03000000, ADC_RES_8BIT = 0x02000000,
  ADC_RES_10BIT = 0x01000000, ADC_RES_12BIT = 0x00000000, ADC_RES_14BIT = 1, ADC_RES_16BIT = 2,
  ADC_RES_6BIT = (0x3 << 3), ADC_RES_8BIT = (0x2 << 3), ADC_RES_10BIT = (0x1 << 3), ADC_RES_12BIT = (0x0 << 3),
  ADC_RES_14BIT = (0xfe), ADC_RES_16BIT = (0xff), ADC_RES_6BIT = 0, ADC_RES_8BIT,
  ADC_RES_10BIT, ADC_RES_12BIT, ADC_RES_14BIT, ADC_RES_16BIT
}
 Possible ADC resolution settings. More...
 

Enumeration Type Documentation

◆ adc_res_t

enum adc_res_t
Enumerator
ADC_RES_6BIT 

not supported by hardware

ADC_RES_7BIT 

ADC resolution: 7 bit.

ADC_RES_8BIT 

not supported by hardware

ADC_RES_9BIT 

ADC resolution: 9 bit.

ADC_RES_10BIT 

ADC resolution: 10 bit.

ADC_RES_12BIT 

ADC resolution: 12 bit.

ADC_RES_14BIT 

not supported by hardware

ADC_RES_16BIT 

not supported by hardware

ADC_RES_6BIT 

not applicable

ADC_RES_8BIT 

not applicable

ADC_RES_10BIT 

ADC resolution: 10 bit.

ADC_RES_12BIT 

ADC resolution: 12 bit.

ADC_RES_14BIT 

not applicable

ADC_RES_16BIT 

not applicable

ADC_RES_6BIT 

not supported

ADC_RES_8BIT 

ADC resolution: 8 bit.

ADC_RES_10BIT 

ADC resolution: 10 bit.

ADC_RES_12BIT 

ADC resolution: 12 bit.

ADC_RES_14BIT 

not supported

ADC_RES_16BIT 

not supported

ADC_RES_6BIT 

not supported

ADC_RES_8BIT 

ADC resolution: 8 bit.

ADC_RES_10BIT 

ADC resolution: 10 bit.

ADC_RES_12BIT 

ADC resolution: 12 bit.

ADC_RES_14BIT 

not supported

ADC_RES_16BIT 

not supported

ADC_RES_6BIT 

ADC resolution: 6 bit.

ADC_RES_8BIT 

ADC resolution: 8 bit.

ADC_RES_10BIT 

ADC resolution: 10 bit.

ADC_RES_12BIT 

ADC resolution: 12 bit.

ADC_RES_14BIT 

ADC resolution: 14 bit (not supported)

ADC_RES_16BIT 

ADC resolution: 16 bit (not supported)

ADC_RES_6BIT 

ADC resolution: 6 bit.

ADC_RES_8BIT 

ADC resolution: 8 bit.

ADC_RES_10BIT 

ADC resolution: 10 bit.

ADC_RES_12BIT 

ADC resolution: 12 bit.

ADC_RES_14BIT 

not applicable

ADC_RES_16BIT 

not applicable

ADC_RES_6BIT 

ADC resolution: 6 bit.

ADC_RES_8BIT 

ADC resolution: 8 bit.

ADC_RES_10BIT 

ADC resolution: 10 bit.

ADC_RES_12BIT 

ADC resolution: 12 bit.

ADC_RES_14BIT 

ADC resolution: 14 bit.

ADC_RES_16BIT 

ADC resolution: 16 bit.

Definition at line 87 of file adc.h.

Function Documentation

◆ adc_init()

int adc_init ( adc_t  line)

The ADC line is initialized in synchronous, blocking mode.

Parameters
[in]lineline to initialize
Returns
0 on success
-1 on invalid ADC line

◆ adc_sample()

int adc_sample ( adc_t  line,
adc_res_t  res 
)

This function blocks until the conversion has finished. Please note, that if more than one line share the same ADC device, and if these lines are sampled at the same time (e.g. from different threads), the one called secondly waits for the first to finish before its conversion starts.

Parameters
[in]lineline to sample
[in]resresolution to use for conversion
Returns
the sampled value on success
-1 if resolution is not applicable