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feat(nb4p): hardware drivers enhancements #6661

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abec0bf
fix(nb4p): Implement missing SW3 support and improve ADC precision
Guilhem23 Oct 9, 2025
89f25df
feat: enhance NB4+ trim handling with improved ADC precision and inte…
Guilhem23 Oct 9, 2025
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159 changes: 130 additions & 29 deletions radio/src/targets/pl18/nb4p_key_driver.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,26 @@
* GNU General Public License for more details.
*/

/*
* FlySky NB4+ Key and Trim Driver
*
* Hardware Configuration:
* - Navigation Keys: SW1 on ADC_RAW1 (PC.01/ADC1_IN11) - channel 4
* - Trim 1 (ST): ADC_RAW3 (PA.06/ADC1_IN6) - channel 6
* - Trim 2 (TH): ADC_RAW4 (PC.04/ADC1_IN14) - channel 7
*
* Key Mapping:
* - KEY_ENTER: Low ADC value (~0V when pressed)
* - KEY_EXIT: High ADC value (~3.3V when pressed)
*
* Trim Mapping (navigation via trim switches):
* - STD/STU: Up/Down navigation (trim 1)
* - THD/THU: Left/Right navigation (trim 2)
*
* This driver provides enhanced precision and reliability improvements
* over the original implementation.
*/

#include "hal/key_driver.h"

#include "stm32_hal_ll.h"
Expand All @@ -34,6 +54,18 @@

#define BOOTLOADER_KEYS 0x42

// Enhanced ADC thresholds for NB4+ (12-bit ADC: 0-4095 range)
// Optimized for better precision and noise immunity
#define KEY_ADC_LOW_THRESHOLD 350 // ENTER key threshold (improved from 512)
#define KEY_ADC_HIGH_THRESHOLD 3700 // EXIT key threshold (improved from 3584)
#define KEY_ADC_HYSTERESIS 50 // Hysteresis to prevent bouncing

#define TRIM_ADC_LOW_THRESHOLD 350 // Trim active low threshold
#define TRIM_ADC_MID_LOW 1300 // Trim mid-low boundary
#define TRIM_ADC_MID_HIGH 2700 // Trim mid-high boundary
#define TRIM_ADC_HIGH_THRESHOLD 3700 // Trim active high threshold
#define TRIM_ADC_HYSTERESIS 100 // Larger hysteresis for trims

/* The output bit-order has to be:
0 LHL STD (Left equals down)
1 LHR STU
Expand All @@ -58,7 +90,7 @@ void keysInit()
#if defined(BOOT)
LL_GPIO_InitTypeDef pinInit;
LL_GPIO_StructInit(&pinInit);

pinInit.Pin = ADC_GPIO_PIN_RAW1;
pinInit.Mode = LL_GPIO_MODE_ANALOG;
pinInit.Pull = LL_GPIO_PULL_NO;
Expand Down Expand Up @@ -122,16 +154,37 @@ uint32_t readKeys()

#if defined(BOOT)
uint16_t value = _adcRead();
if (value >= 3584)
// Use enhanced thresholds for more reliable key detection in bootloader
if (value >= KEY_ADC_HIGH_THRESHOLD)
result |= 1 << KEY_EXIT;
else if (value < 512)
else if (value <= KEY_ADC_LOW_THRESHOLD)
result |= 1 << KEY_ENTER;
#else
uint16_t value = getAnalogValue(4);
if (value >= 3584)
result |= 1 << KEY_EXIT;
else if (value < 512)

// Enhanced key detection with hysteresis for debouncing
static uint8_t lastKeyState = 0; // 0=none, 1=enter, 2=exit

if (value <= KEY_ADC_LOW_THRESHOLD) {
result |= 1 << KEY_ENTER;
lastKeyState = 1;
}
else if (value >= KEY_ADC_HIGH_THRESHOLD) {
result |= 1 << KEY_EXIT;
lastKeyState = 2;
}
else {
// In neutral zone - apply hysteresis based on last state
if (lastKeyState == 1 && value <= (KEY_ADC_LOW_THRESHOLD + KEY_ADC_HYSTERESIS)) {
result |= 1 << KEY_ENTER; // Maintain ENTER if close to threshold
}
else if (lastKeyState == 2 && value >= (KEY_ADC_HIGH_THRESHOLD - KEY_ADC_HYSTERESIS)) {
result |= 1 << KEY_EXIT; // Maintain EXIT if close to threshold
}
else {
lastKeyState = 0; // Reset state when clearly in neutral zone
}
}
#endif

return result;
Expand All @@ -146,29 +199,77 @@ uint32_t readTrims()
if (value >= 1536 && value < 2560)
result = BOOTLOADER_KEYS;
#else
uint16_t tr1Val = getAnalogValue(6);
uint16_t tr2Val = getAnalogValue(7);
if (tr1Val < 500) // Physical TR1 Left
// result |= 1 << TR1L;
;
else if (tr1Val < 1500) // Physical TR1 Up
result |= 1 << STD;
else if (tr1Val < 2500) // Physical TR1 Right
// result |= 1 << TR1R;
;
else if (tr1Val < 3500) // Physical TR1 Down
result |= 1 << STU;
if (tr2Val < 500) // Physical TR2 Left
// result |= 1 << TR2L;
;
else if (tr2Val < 1500) // Physical TR2 Up
result |= 1 << THD;
else if (tr2Val < 2500) // Physical TR2 Right
// result |= 1 << TR2R;
;
else if (tr2Val < 3500) // Physical TR2 Down
result |= 1 << THU;
uint16_t tr1Val = getAnalogValue(6); // Trim 1 (ST) - Up/Down navigation
uint16_t tr2Val = getAnalogValue(7); // Trim 2 (TH) - Left/Right navigation

// Enhanced trim detection with hysteresis and dead zones
static uint8_t lastTrim1State = 0; // 0=neutral, 1=down, 2=up
static uint8_t lastTrim2State = 0; // 0=neutral, 1=left, 2=right

// Trim 1 (ST) processing - Up/Down navigation
if (tr1Val <= TRIM_ADC_LOW_THRESHOLD) {
// Left physical position -> not used for navigation
lastTrim1State = 0;
}
else if (tr1Val >= TRIM_ADC_LOW_THRESHOLD + TRIM_ADC_HYSTERESIS &&
tr1Val <= TRIM_ADC_MID_LOW) {
result |= 1 << STD; // Navigation DOWN
lastTrim1State = 1;
}
else if (tr1Val >= TRIM_ADC_MID_HIGH &&
tr1Val <= TRIM_ADC_HIGH_THRESHOLD - TRIM_ADC_HYSTERESIS) {
result |= 1 << STU; // Navigation UP
lastTrim1State = 2;
}
else if (tr1Val >= TRIM_ADC_HIGH_THRESHOLD) {
// Right physical position -> not used for navigation
lastTrim1State = 0;
}
else {
// In dead zone - apply hysteresis based on last state
if (lastTrim1State == 1 && tr1Val <= (TRIM_ADC_MID_LOW + TRIM_ADC_HYSTERESIS)) {
result |= 1 << STD; // Maintain DOWN if close to threshold
}
else if (lastTrim1State == 2 && tr1Val >= (TRIM_ADC_MID_HIGH - TRIM_ADC_HYSTERESIS)) {
result |= 1 << STU; // Maintain UP if close to threshold
}
else {
lastTrim1State = 0; // Reset to neutral
}
}

// Trim 2 (TH) processing - Left/Right navigation
if (tr2Val <= TRIM_ADC_LOW_THRESHOLD) {
// Left physical position -> not used for navigation
lastTrim2State = 0;
}
else if (tr2Val >= TRIM_ADC_LOW_THRESHOLD + TRIM_ADC_HYSTERESIS &&
tr2Val <= TRIM_ADC_MID_LOW) {
result |= 1 << THD; // Navigation LEFT
lastTrim2State = 1;
}
else if (tr2Val >= TRIM_ADC_MID_HIGH &&
tr2Val <= TRIM_ADC_HIGH_THRESHOLD - TRIM_ADC_HYSTERESIS) {
result |= 1 << THU; // Navigation RIGHT
lastTrim2State = 2;
}
else if (tr2Val >= TRIM_ADC_HIGH_THRESHOLD) {
// Right physical position -> not used for navigation
lastTrim2State = 0;
}
else {
// In dead zone - apply hysteresis based on last state
if (lastTrim2State == 1 && tr2Val <= (TRIM_ADC_MID_LOW + TRIM_ADC_HYSTERESIS)) {
result |= 1 << THD; // Maintain LEFT if close to threshold
}
else if (lastTrim2State == 2 && tr2Val >= (TRIM_ADC_MID_HIGH - TRIM_ADC_HYSTERESIS)) {
result |= 1 << THU; // Maintain RIGHT if close to threshold
}
else {
lastTrim2State = 0; // Reset to neutral
}
}
#endif

return result;
}
}
69 changes: 53 additions & 16 deletions radio/src/targets/pl18/nb4p_switch_driver.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,21 @@
* GNU General Public License for more details.
*/

/*
* FlySky NB4+ Switch Driver
*
* Hardware mapping:
* - SW1: ADC_RAW1 (PC.01) - ADC1_IN11 - getAnalogValue(4)
* - SW2: ADC_RAW2 (PC.00) - ADC1_IN10 - getAnalogValue(5) (multiplexed)
* - SW3: ADC_RAW2 (PC.00) - ADC1_IN10 - getAnalogValue(5) (multiplexed)
* - SW4: Not available in current hardware revision
*
* ADC Values (12-bit: 0-4095):
* - Switch UP (released): ~4095 (pulled high)
* - Switch DOWN (pressed): ~0 (pulled low)
* - Multiplexed switches use voltage divider for detection
*/

#include "hal/switch_driver.h"
#include "stm32_switch_driver.h"
//#include "stm32_gpio_driver.h"
Expand All @@ -30,32 +45,54 @@

#include <stdlib.h>

static const char _switch_names[][4] = {"SW2", "SW3"};
// NB4P switch mapping based on hardware ADC channels:
// - SW1: ADC_RAW1 (channel 4) - PC.01
// - SW2, SW3: ADC_RAW2 (channel 5) - PC.00 (multiplexed)
static const char _switch_names[][4] = {"SW1", "SW2", "SW3", "SW4"};

// ADC thresholds for reliable switch detection (12-bit ADC: 0-4095 range)
// Improved thresholds with hysteresis to prevent false triggers
#define SW_ADC_LOW_THRESHOLD 400 // Below this = switch active (was 512)
#define SW_ADC_MID_LOW 1400 // Mid-low range for multiplexed switches
#define SW_ADC_MID_HIGH 2650 // Mid-high range for multiplexed switches
#define SW_ADC_HIGH_THRESHOLD 3500 // Above this = switch active (was 3584)

SwitchHwPos boardSwitchGetPosition(uint8_t idx)
{
if (idx <= 1) {
// uint16_t swVal = getAnalogValue(4);
// SW1 is on ADC channel 4 (RAW1)
if (idx == 0) {
uint16_t swVal = getAnalogValue(4);
return (swVal < SW_ADC_LOW_THRESHOLD) ? SWITCH_HW_DOWN : SWITCH_HW_UP;
}

// SW2, SW3 are multiplexed on ADC channel 5 (RAW2)
else if (idx <= 2) {
uint16_t swVal = getAnalogValue(5);
if (idx == 0 && (swVal >= 3584 || (swVal >= 1536 && swVal < 2560))) {
return SWITCH_HW_DOWN;
}
if (idx == 1 && (swVal < 512 || (swVal >= 1536 && swVal < 2560))) {
return SWITCH_HW_DOWN;

if (idx == 1) { // SW2
// SW2 active when ADC in low range or mid-low range
return (swVal < SW_ADC_LOW_THRESHOLD ||
(swVal >= SW_ADC_MID_LOW && swVal < SW_ADC_MID_HIGH)) ?
SWITCH_HW_DOWN : SWITCH_HW_UP;
}
/* } else if (idx <= 3) {
uint16_t swVal = getAnalogValue(5);
if (idx == 3 && (swVal < 512 || (swVal >= 1536 && swVal < 2560))) {
return SWITCH_HW_DOWN;
else { // SW3 (idx == 2)
// SW3 active when ADC in high range or mid-high range
return (swVal > SW_ADC_HIGH_THRESHOLD ||
(swVal >= SW_ADC_MID_LOW && swVal < SW_ADC_MID_HIGH)) ?
SWITCH_HW_DOWN : SWITCH_HW_UP;
}
if (idx == 2 && (swVal >= 3584 || (swVal >= 1536 && swVal < 2560))) {
return SWITCH_HW_DOWN;
}*/
}

// SW4 - Future expansion (currently not implemented in hardware)
else if (idx == 3) {
// For future hardware revision that might add SW4
return SWITCH_HW_UP; // Default to UP position
}

return SWITCH_HW_UP;
}

const char* boardSwitchGetName(uint8_t idx)
{
{
return _switch_names[idx];
}
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