Description

C interface for the Linux IIO ADC driver.

The Robotics cape and BeagleBone Blue include two voltage dividers for safe measurement of the 2-cell lithium battery voltage and the voltage of any power source connected to the 9-18V DC power jack. These can be read with c_adc_batt() and rc_adc_dc_jack()

There is also a 6-pin JST-SH socket on the Cape for connecting up to 4 potentiometers or general use analog signals. The pinout of this socket is as follows:

1 - Ground
2 - VDD_ADC (1.8V)
3 - AIN0
4 - AIN1
5 - AIN2
6 - AIN3

All 8 ADC channels on the Sitara including the 4 listed above can be read with rc_adc_read_raw(int ch) which returns the raw integer output of the 12-bit ADC. rc_adc_read_volt(int ch) additionally converts this raw value to a voltage.

See the rc_test_adc example for sample use case.

Functions
int	rc_adc_init (void)
	initializes the analog to digital converter for reading More...

int	rc_adc_cleanup (void)
	Cleans up the ADC subsystem. More...

int	rc_adc_read_raw (int ch)
	reads the raw integer ADC value for a particular channel More...

double	rc_adc_read_volt (int ch)
	reads an adc voltage. More...

double	rc_adc_batt (void)
	reads the voltage of the 2-cell Lithium battery More...

double	rc_adc_dc_jack (void)
	Reads the voltage of the 9-18v DC jack. More...

Function Documentation

◆ rc_adc_init()

int rc_adc_init ( void )

initializes the analog to digital converter for reading

Returns: 0 on success, -1 on failure.

Examples:: rc_balance.c, rc_check_battery.c, rc_dsm_passthrough.c, rc_test_adc.c, and rc_test_servos.c.

◆ rc_adc_cleanup()

int rc_adc_cleanup ( void )

Cleans up the ADC subsystem.

Call before your program closes down

Returns: 0 on success, -1 on failure.

Examples:: rc_check_battery.c, rc_dsm_passthrough.c, rc_test_adc.c, and rc_test_servos.c.

◆ rc_adc_read_raw()

int rc_adc_read_raw ( int ch )

reads the raw integer ADC value for a particular channel

Parameters

[in] ch channel 0-7

Returns: 16-bit adc reading on success, -1 on failure.

◆ rc_adc_read_volt()

double rc_adc_read_volt ( int ch )

reads an adc voltage.

Parameters

[in] ch channel 0-7

Returns: voltage from 0-1.8v or -1 on error

Examples:: rc_test_adc.c.

◆ rc_adc_batt()

double rc_adc_batt ( void )

reads the voltage of the 2-cell Lithium battery

Returns: voltage of battery or -1 on failure

Examples:: rc_balance.c, rc_check_battery.c, rc_dsm_passthrough.c, rc_test_adc.c, and rc_test_servos.c.

◆ rc_adc_dc_jack()

double rc_adc_dc_jack ( void )

Reads the voltage of the 9-18v DC jack.

Returns: Voltage at DC jack or -1 on failure

Examples:: rc_check_battery.c, and rc_test_adc.c.