Documentation Index
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The ADC application reads analog voltages from the COMM header’s ADC1 and ADC2 pins and maps them to a motor output level. It is the standard choice for physical throttle and brake levers that output a voltage proportional to position.
Voltage range
Default voltage mapping from appconf_default.h:
| Parameter | Default | Description |
|---|
voltage_start | 0.9 V | Voltage at which throttle output begins. |
voltage_end | 3.0 V | Voltage at which throttle reaches maximum. |
voltage_center | 2.0 V | Center voltage for bidirectional control types. |
voltage_min | 0.0 V | Below this voltage the signal is treated as a fault. |
voltage_max | 3.5 V | Above this voltage the signal is treated as a fault. |
voltage2_start | 0.9 V | Start voltage for the second ADC channel (brake). |
voltage2_end | 3.0 V | End voltage for the second ADC channel (brake). |
If the measured voltage falls outside voltage_min–voltage_max, the application treats it as a disconnected sensor and cuts motor output. Ensure your sensor voltage never exceeds 3.3 V on standard VESC hardware.
Control types
typedef enum {
ADC_CTRL_TYPE_NONE = 0,
ADC_CTRL_TYPE_CURRENT,
ADC_CTRL_TYPE_CURRENT_REV_CENTER,
ADC_CTRL_TYPE_CURRENT_REV_BUTTON,
ADC_CTRL_TYPE_CURRENT_REV_BUTTON_BRAKE_ADC,
ADC_CTRL_TYPE_CURRENT_REV_BUTTON_BRAKE_CENTER,
ADC_CTRL_TYPE_CURRENT_NOREV_BRAKE_CENTER,
ADC_CTRL_TYPE_CURRENT_NOREV_BRAKE_BUTTON,
ADC_CTRL_TYPE_CURRENT_NOREV_BRAKE_ADC,
ADC_CTRL_TYPE_DUTY,
ADC_CTRL_TYPE_DUTY_REV_CENTER,
ADC_CTRL_TYPE_DUTY_REV_BUTTON,
ADC_CTRL_TYPE_PID,
ADC_CTRL_TYPE_PID_REV_CENTER,
ADC_CTRL_TYPE_PID_REV_BUTTON
} adc_control_type;
| Suffix | Meaning |
|---|
| (none) | Forward only, no brake. |
REV_CENTER | Reverse when ADC1 is below center voltage. |
REV_BUTTON | Reverse when a dedicated button is pressed. |
BRAKE_ADC | Braking current set by ADC2 voltage. |
BRAKE_CENTER | Braking when ADC1 is below center voltage. |
BRAKE_BUTTON | Braking when a dedicated button is pressed. |
NOREV | Forward-only mode regardless of input. |
Configuration struct
typedef struct {
adc_control_type ctrl_type;
float hyst;
float voltage_start;
float voltage_end;
float voltage_min;
float voltage_max;
float voltage_center;
float voltage2_start;
float voltage2_end;
bool use_filter;
SAFE_START_MODE safe_start;
uint8_t buttons;
bool voltage_inverted;
bool voltage2_inverted;
float throttle_exp;
float throttle_exp_brake;
thr_exp_mode throttle_exp_mode;
float ramp_time_pos;
float ramp_time_neg;
bool multi_esc;
bool tc;
float tc_max_diff;
uint32_t update_rate_hz;
} adc_config;
Key parameters
| Field | Default | Description |
|---|
hyst | 0.15 | Deadband around center/off point (normalised). |
use_filter | true | Applies a moving-average filter over FILTER_SAMPLES (5) readings. |
safe_start | SAFE_START_REGULAR | Requires voltage to return to idle range before output is allowed. |
update_rate_hz | 500 Hz | ADC polling rate. |
ramp_time_pos | 0.3 s | Positive output ramp time. |
ramp_time_neg | 0.1 s | Negative output ramp time. |
voltage_inverted | false | Inverts ADC1 mapping (full voltage = idle). |
voltage2_inverted | false | Inverts ADC2 mapping. |
multi_esc | true | Forwards command over CAN bus. |
Throttle curve
The throttle_exp and throttle_exp_brake fields tune the exponential response curve, controlled by throttle_exp_mode:
typedef enum {
THR_EXP_EXPO = 0,
THR_EXP_NATURAL,
THR_EXP_POLY
} thr_exp_mode;
0.0 gives a linear response. Positive values make the initial part of the throttle softer.
Runtime API
void app_adc_start(bool use_rx_tx);
void app_adc_stop(void);
void app_adc_configure(adc_config *conf);
float app_adc_get_decoded_level(void);
float app_adc_get_voltage(void);
float app_adc_get_decoded_level2(void);
float app_adc_get_voltage2(void);
bool app_adc_range_ok(void);
void app_adc_detach_adc(int detach);
void app_adc_adc1_override(float val);
void app_adc_adc2_override(float val);
app_adc_range_ok returns false when either ADC channel voltage is outside the configured min/max bounds, which can be polled to detect a disconnected sensor.