AP_Button: allow PWM to be used for button input

libraries/AP_Button/AP_Button.cpp

@@ -69,6 +69,34 @@ const AP_Param::GroupInfo AP_Button::var_info[] = {
     // @Range: 0 3600
     AP_GROUPINFO("REPORT_SEND", 5, AP_Button, report_send_time, 10),
 
+    // @Param: OPTIONS1
+    // @DisplayName: Button Pin 1 Options
+    // @Description: Options for Pin 1
+    // @User: Standard
+    // @Bitmask: 0:PWM Input,1:InvertInput
+    AP_GROUPINFO("OPTIONS1",  6, AP_Button, options[0], 0),
+
+    // @Param: OPTIONS2
+    // @DisplayName: Button Pin 2 Options
+    // @Description: Options for Pin 2
+    // @User: Standard
+    // @Bitmask: 0:PWM Input,1:InvertInput
+    AP_GROUPINFO("OPTIONS2",  7, AP_Button, options[1], 0),
+
+    // @Param: OPTIONS3
+    // @DisplayName: Button Pin 3 Options
+    // @Description: Options for Pin 3
+    // @User: Standard
+    // @Bitmask: 0:PWM Input,1:InvertInput
+    AP_GROUPINFO("OPTIONS3",  8, AP_Button, options[2], 0),
+
+    // @Param: OPTIONS4
+    // @DisplayName: Button Pin 4 Options
+    // @Description: Options for Pin 4
+    // @User: Standard
+    // @Bitmask: 0:PWM Input,1:InvertInput
+    AP_GROUPINFO("OPTIONS4",  9, AP_Button, options[3], 0),
+
     AP_GROUPEND    
 };
 
@@ -107,6 +135,31 @@ void AP_Button::update(void)
         hal.scheduler->register_timer_process(FUNCTOR_BIND_MEMBER(&AP_Button::timer_update, void));        
     }
 
+    // act on any changes in state
+    {
+        WITH_SEMAPHORE(last_debounced_change_ms_sem);
+        if (last_debounced_change_ms > last_debounce_ms) {
+            last_debounce_ms = last_debounced_change_ms;
+        }
+    }
+
+    // update the PWM state:
+    uint8_t new_pwm_state = 0;
+    for (uint8_t i=0; i<AP_BUTTON_NUM_PINS; i++) {
+        if (!is_pwm_input(i)) {
+            // not a PWM input
+            continue;
+        }
+        const uint16_t pwm_us = pwm_pin_source[i].get_pwm_us();
+        // these values are the same as used in RC_Channel:
+        new_pwm_state |= pwm_us > 1800 && pwm_us < 2200;
+    }
+    if (new_pwm_state != pwm_state) {
+        pwm_state = new_pwm_state;
+        last_debounced_change_ms = AP_HAL::millis64();
+    }
+
+    // act on any changes in state
     if (last_change_time_ms != 0 &&
         (AP_HAL::millis() - last_report_ms) > AP_BUTTON_REPORT_PERIOD_MS &&
         (AP_HAL::millis64() - last_change_time_ms) < report_send_time*1000ULL) {
@@ -126,7 +179,11 @@ bool AP_Button::get_button_state(uint8_t number)
     if (number == 0 || number > AP_BUTTON_NUM_PINS) {
         return false;
     }
-    
+
+    if (is_pwm_input(number-1)) {
+        return (pwm_state & (1U<<(number-1)));
+    }
+
     return ( ((1 << (number - 1)) & debounce_mask) != 0);
 };
 
@@ -140,8 +197,12 @@ uint8_t AP_Button::get_mask(void)
         if (pin[i] == -1) {
             continue;
         }
+        if (is_pwm_input(i)) {
+            continue;
+        }
         mask |= hal.gpio->read(pin[i]) << i;
     }
+
     return mask;
 }
 
@@ -159,9 +220,11 @@ void AP_Button::timer_update(void)
         last_mask = mask;
         last_change_time_ms = now;
     }
-    if ((now - last_change_time_ms) > DEBOUNCE_MS) {
+    if (debounce_mask != last_mask &&
+        (now - last_change_time_ms) > DEBOUNCE_MS) {
         // crude de-bouncing, debounces all buttons as one, not individually
         debounce_mask = last_mask;
+        last_debounced_change_ms = now;
     }
 }
 
@@ -170,10 +233,11 @@ void AP_Button::timer_update(void)
  */
 void AP_Button::send_report(void)
 {
+    const uint8_t mask = last_mask | pwm_state;
     const mavlink_button_change_t packet{
             time_boot_ms: AP_HAL::millis(),
-            last_change_ms: uint32_t(last_change_time_ms),
-            state: last_mask
+            last_change_ms: uint32_t(last_debounce_ms),
+            state: mask,
     };
     gcs().send_to_active_channels(MAVLINK_MSG_ID_BUTTON_CHANGE,
                                   (const char *)&packet);
@@ -186,9 +250,14 @@ void AP_Button::send_report(void)
 void AP_Button::setup_pins(void)
 {
     for (uint8_t i=0; i<AP_BUTTON_NUM_PINS; i++) {
+        if (is_pwm_input(i)) {
+            pwm_pin_source[i].set_pin(pin[i], "Button");
+            continue;
+        }
         if (pin[i] == -1) {
             continue;
         }
+
         hal.gpio->pinMode(pin[i], HAL_GPIO_INPUT);
         // setup pullup
         hal.gpio->write(pin[i], 1);

libraries/AP_Button/AP_Button.h

@@ -51,6 +51,11 @@ private:
 
     AP_Int8 enable;
     AP_Int8 pin[AP_BUTTON_NUM_PINS];
+    AP_Int8 options[AP_BUTTON_NUM_PINS];  // if a pin's bit is set then it uses PWM assertion
+
+    bool is_pwm_input(uint8_t n) const {
+        return ((uint8_t)options[n].get() & (1U<<0)) != 0;
+    }
 
     // number of seconds to send change notifications
     AP_Int16 report_send_time;
@@ -61,6 +66,17 @@ private:
     // debounced button press mask
     uint8_t debounce_mask;
 
+    // current state of PWM pins:
+    uint8_t pwm_state;
+
+    // mask indicating which action was most recent taken for pins
+    uint8_t state_actioned_mask;
+
+    // pwm sources are used when using PWM on the input
+    AP_HAL::PWMSource pwm_pin_source[AP_BUTTON_NUM_PINS];
+
+    uint64_t last_debounced_change_ms;
+
     // when the mask last changed
     uint64_t last_change_time_ms;