OMNIBUSF4 Target Support README
===============================
"OmnibusF4" is not a product name per se, but rather a design spec
that many product vendors within the drone flight management unit
(FMU) community adhere to. The spec defines the major components, and
how those components are wired into the STM32F405RGT6 microcontroller.
Airbot is one such vendor, and they publish a schematic here:
http://bit.ly/obf4pro
Other software that supports the OmnibusF4 family include Betaflight,
iNAV, and many others. PX4 recently added support as well. No code
from any of those sources is included in this port.
Since OmnibusF4 is a drone FMU, most of its IO is already allocated to
FMU-specific tasks. As such, we don't need to make the board support
package as flexible as, say, an STM32F4 Discovery board.
The following are some of the committed IO pins. Most of the pins not
mentioned here are inaccessible, the details vary by board vendor:
io peripheral signal notes
==================================
XIN 8MHz crystal oscillator
PB0 TIM3 CH3 S1_OUT motor 1 PWM output
PB1 TIM3 CH4 S2_OUT motor 2 PWM output
PA3 TIM2 CH4 S3_OUT motor 3 PWM output
PA2 TIM2 CH3 S4_OUT motor 4 PWM output
PA1 TIM2 CH2 S5_OUT motor 5 PWM output
PA8 TIM1 CH4 S6_OUT motor 6 PWM output
PA4 SPI1 SPI1_NSS mpu6000
PA5 SPI1 SPI1_SCL
PA6 SPI1 SPI1_MISO
PA7 SPI1 SPI1_MOSI
PC4 GPIO GYRO_INT mpu6000 EXTI
PB10 UART3/I2C UART3_TX ttl UART tx or i2c_scl (used as console)
PB11 UART3/I2C UART3_RX ttl UART rx or i2c_sda (used as console)
PB9 RC_CH2 (rx pwm input)
PB8 RC_CH1 (rx pwm input)
PC9 RC_CH6 (rx pwm input)
PC8 RC_CH5 (rx pwm input)
PC7 RC_CH4 or USART6_RX (ttl)
PC6 RC_CH3 or USART6_TX (ttl)
PB7 GPIO SD_DET SD card detection pin (low when card inserted)
PB5 GPIO STAT LED output (active low)
PB4 GPIO BUZZER buzzer output (active low)
PD2 GPIO LED_STRIP one-wire interface for LED strips
PC12 SPI3 SPI3_MOSI bmp280 barometer (if populated) and/or max7456 OSD
PC11 SPI3 SPI3_MISO
PC10 SPI3 SPI3_SCL
PA15 GPIO SPI3_NSS OSD NSS
PB3 GPIO BARO_CS bmp280 NSS (if populated)
PA12 OTG USB_DP
PA11 OTG USB_DN
PA10 UART1 USART1_RX SBUS_IN (through inverter) or PPM
PA9 UART1 USART1_TX
PB15 SPI2 SPI2_MOSI sd/mmc card interface
PB14 SPI2 SPI2_MISO
PB13 SPI2 SPI2_SCLK
PB12 SPI2 SPI2_NSS
Build Instructions
==================
The boards/arm/stm32/omnibusf4/nsh/defconfig file creates a basic setup, and
includes drivers for all supported onboard chips. The console and
command prompt are sent to USART3.
