px4fmu-v5 Remove GPIO_RC_OUT and vetted RC_IN wiring

   Removed the legacy FMUv4 define that was activating a nonexistent
   pull up and on some HW driving the PPM_IN aka RC_IN aka SPEKTRUM_RX
   to VDD.

   Also detailed the connections of this pins for the board.

   The simplest connection is RC_IN to a timer capture pin
   and a UART.
   In this case the UART_RX pin and just be left as is.
   While the pin can be configured as the PPM_IN (Timer capture)
   or as SPEKTRUM_R
   facilitate binding.

  Renamed the macros and defines to be more explicit as to what
  Is being done and the sense of the parameters

src/drivers/boards/px4fmu-v5/board_config.h

@@ -338,18 +338,26 @@ __BEGIN_DECLS
 #define GPIO_LED_SAFETY         /* PE12 */ (GPIO_OUTPUT|GPIO_PUSHPULL|GPIO_SPEED_2MHz|GPIO_OUTPUT_SET|GPIO_PORTE|GPIO_PIN12)
 #define GPIO_BTN_SAFETY         /* PE10 */ (GPIO_INPUT|GPIO_PULLUP|GPIO_PORTE|GPIO_PIN10)
 
-#define INVERT_RC_INPUT(_s)		board_rc_input(_s);
+#define INVERT_RC_INPUT(_invert_true)      board_rc_input(_invert_true);
 
 
 /* Power switch controls ******************************************************/
 
-#define POWER_SPEKTRUM(_s)      px4_arch_gpiowrite(GPIO_SPEKTRUM_POWER_EN, (1-_s))
-#define SPEKTRUM_RX_AS_UART()   px4_arch_configgpio(GPIO_USART6_RX) /* NOT FMUv5 test HW ONLY*/
+#define SPEKTRUM_POWER(_on_true)           px4_arch_gpiowrite(GPIO_SPEKTRUM_POWER_EN, (_on_true))
 
-// FMUv5 has a separate GPIO for serial RC output
-#define GPIO_RC_OUT            /* PG9 */ (GPIO_OUTPUT|GPIO_PUSHPULL|GPIO_SPEED_2MHz|GPIO_OUTPUT_SET|GPIO_PORTG|GPIO_PIN9)
-#define SPEKTRUM_RX_AS_GPIO()   px4_arch_configgpio(GPIO_RC_OUT)
-#define SPEKTRUM_RX_HIGH(_s)    px4_arch_gpiowrite(GPIO_RC_OUT, (_s))
+/*
+ * FMUv5 has a separate RC_IN
+ *
+ * GPIO PPM_IN on PI5 T8CH1
+ * SPEKTRUM_RX (it's TX or RX in Bind) on UART6 PG9 (NOT FMUv5 test HW ONLY)
+ *   In version is possible in the UART
+ * and can drive  GPIO PPM_IN as an output
+ */
+
+#define GPIO_PPM_IN_AS_OUT             (GPIO_OUTPUT|GPIO_PUSHPULL|GPIO_SPEED_2MHz|GPIO_OUTPUT_SET|GPIO_PORTI|GPIO_PIN5)
+#define SPEKTRUM_RX_AS_GPIO_OUTPUT()   px4_arch_configgpio(GPIO_PPM_IN_AS_OUT)
+#define SPEKTRUM_RX_AS_UART()          /* Can be left as uart */
+#define SPEKTRUM_OUT(_one_true)        px4_arch_gpiowrite(GPIO_PPM_IN_AS_OUT, (_one_true))
 
 #define SDIO_SLOTNO             0  /* Only one slot */
 #define SDIO_MINOR              0

src/drivers/boards/px4fmu-v5/px4fmu_init.c

@@ -257,10 +257,6 @@ stm32_boardinitialize(void)
 	stm32_configgpio(GPIO_LED_SAFETY);
 	stm32_configgpio(GPIO_BTN_SAFETY);
 
-#ifdef GPIO_RC_OUT
-	stm32_configgpio(GPIO_RC_OUT);      /* Serial RC output pin */
-#endif
-
 	/* configure SPI interfaces */
 	stm32_spiinitialize();