HAL_ChibiOS: hwdef: add README.md for PixSurveyA1

libraries/AP_HAL_ChibiOS/hwdef/PixSurveyA1/README.md

@@ -0,0 +1,37 @@
+## PixSurveyA1 Flight Controller
+The flight controller is based on FMUv3, with added MPU9250 or ICM20948 internal compass support
+
+## Features
+•	STM32F427VIT6 and STM32F103C8T6 microcontroller
+
+•	Three IMUs, one MPU6000(SPI), one ICM20602(SPI), one ICM20948 or MPU9250(SPI)
+
+•	internal heater for IMUs temperature control
+
+•	internal Soft Rubber Damping Ball isolation for  interna IMUs
+
+•	Two barometers, MS5611(SPI)
+
+•	Internal compass use MPU9250 or ICM20948
+
+•	builtin RAMTRON(SPI)
+
+•	microSD card slot
+
+•	5 UARTs plus USB(Type-C)
+
+•	PPM & S.Bus input
+
+•	14 PWM outputs
+
+•	two I2C and two CAN ports
+
+•	one S.Bus output
+
+•	External Buzzer
+
+•	two voltage & current monitoring and servo rail voltage monitoring
+
+•	servo rail BEC independent power input for servos
+ 
+•	external safety Switch