AP_IOMCU: implement DSM bind

libraries/AP_IOMCU/iofirmware/iofirmware.cpp

@@ -168,6 +168,10 @@ void AP_IOMCU_FW::init()
     adc_init();
     sbus_out_init();
 
+    // power on spektrum port
+    palSetLineMode(HAL_GPIO_PIN_SPEKTRUM_PWR_EN, PAL_MODE_OUTPUT_PUSHPULL);
+    palSetLine(HAL_GPIO_PIN_SPEKTRUM_PWR_EN);
+
     // we do no allocations after setup completes
     reg_status.freemem = hal.util->available_memory();
 }
@@ -227,6 +231,9 @@ void AP_IOMCU_FW::update()
         safety_update();
         rcout_mode_update();
         hal.rcout->timer_tick();
+        if (dsm_bind_state) {
+            dsm_bind_step();
+        }
     }
 }
 
@@ -470,6 +477,7 @@ bool AP_IOMCU_FW::handle_code_write()
                 palSetLine(HAL_GPIO_PIN_SBUS_OUT_EN);
             }
             break;
+
         case PAGE_REG_SETUP_HEATER_DUTY_CYCLE:
             reg_setup.heater_duty_cycle = rx_io_packet.regs[0];
             last_heater_ms = last_ms;
@@ -492,6 +500,10 @@ bool AP_IOMCU_FW::handle_code_write()
             reg_setup.ignore_safety = rx_io_packet.regs[0];
             ((ChibiOS::RCOutput *)hal.rcout)->set_safety_mask(reg_setup.ignore_safety);
             break;
+
+        case PAGE_REG_SETUP_DSM_BIND:
+            dsm_bind_state = 1;
+            break;
             
         default:
             break;
@@ -663,6 +675,58 @@ void AP_IOMCU_FW::fill_failsafe_pwm(void)
     }
 }
 
+/*
+  perform a DSM bind operation
+ */
+void AP_IOMCU_FW::dsm_bind_step(void)
+{
+    uint32_t now = last_ms;
+    switch (dsm_bind_state) {
+    case 1:
+        palSetLineMode(HAL_GPIO_PIN_SPEKTRUM_PWR_EN, PAL_MODE_OUTPUT_PUSHPULL);
+        palClearLine(HAL_GPIO_PIN_SPEKTRUM_PWR_EN);
+        palSetLineMode(HAL_GPIO_PIN_SPEKTRUM_OUT, PAL_MODE_OUTPUT_PUSHPULL);
+        palSetLine(HAL_GPIO_PIN_SPEKTRUM_OUT);
+        dsm_bind_state = 2;
+        last_dsm_bind_ms = now;
+        break;
+
+    case 2:
+        if (now - last_dsm_bind_ms >= 500) {
+            palSetLine(HAL_GPIO_PIN_SPEKTRUM_PWR_EN);
+            dsm_bind_state = 3;
+            last_dsm_bind_ms = now;
+        }
+        break;
+
+    case 3: {
+        if (now - last_dsm_bind_ms >= 72) {
+            // 9 pulses works with all satellite receivers, and supports the highest
+            // available protocol
+            const uint8_t num_pulses = 9;
+            for (uint8_t i=0; i<num_pulses; i++) {
+                hal.scheduler->delay_microseconds(120);
+                palClearLine(HAL_GPIO_PIN_SPEKTRUM_OUT);
+                hal.scheduler->delay_microseconds(120);
+                palSetLine(HAL_GPIO_PIN_SPEKTRUM_OUT);
+            }
+            last_dsm_bind_ms = now;
+            dsm_bind_state = 4;
+        }
+        break;
+    }
+
+    case 4:
+        if (now - last_dsm_bind_ms >= 50) {
+            // set back as alternate function with pullup for UART input
+            palSetLineMode(HAL_GPIO_PIN_SPEKTRUM_OUT, PAL_MODE_STM32_ALTERNATE_PUSHPULL);
+            palSetLine(HAL_GPIO_PIN_SPEKTRUM_OUT);
+            dsm_bind_state = 0;
+        }
+        break;
+    }
+}
+
 AP_HAL_MAIN();
 
 

libraries/AP_IOMCU/iofirmware/iofirmware.h

@@ -35,6 +35,7 @@ private:
     uint16_t mix_output_angle(uint8_t channel, int16_t angle) const;
     uint16_t mix_output_range(uint8_t channel, int16_t value) const;
     int16_t mix_elevon_vtail(int16_t angle1, int16_t angle2, bool first_output) const;
+    void dsm_bind_step(void);
 
     struct PACKED {
         /* default to RSSI ADC functionality */
@@ -128,5 +129,7 @@ private:
     uint32_t last_status_ms;
     uint32_t last_ms;
     uint32_t loop_counter;
+    uint8_t dsm_bind_state;
+    uint32_t last_dsm_bind_ms;
 };