IC selection

Poundering.typ

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+= RP2350 Flight Controller
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+Ok so the basic thing is that :
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+I am a FPV pilot and I have built a few FPV drones. I am also a embeded engeneer and I want to try to build my own FC.
+
+I want that FC to be quite unique in at least a few ways and I have no experience in using STM32 MCU's that are often used in the industry for that kind of application.
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+I am more experienced and like a lot the MCU's from Raspbberry the Rp2040 and 2350.
+
+Lucky me, Betaflight just added early support for those microcontrollers and except from my fellow Swiss guy behind madflight i dont hink I can find any one to buy. And even then, the madflight is not really about having a serious alternative to the regular FC's on the market and more about prototyping and learning.
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+So basically I want to build a fully featured flight controller in the same class as ones you can find online and that can drive a normal 4in1 ESC (Maybe later a full stack design will be possible)
+
+=== MCU
+
+I am going to be using the SC1512-A4 as its a rp2350 type B with onboard flash. It will be very nice because there is a lot of IO, its easy to route and I will not have to wire an external flash which is nice on cost and on routing.
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+While it does not need any external flash it still needs a few components.
+
+I should be using the ABM8-272-T3 as recommended by the Raspbberry guide but its not in stock so I will be using the MP12641 which should work and is even cheaper.
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+I will use those TL3315NF160Q buttons for RST and BOOTSEL. They are very low profile so I hope they are still usable.
+
+
+=== IMU
+
+The IMU is hard to source as the well known names for these are almost everytwhere out of stock which is a pain.
+
+I will stick with the old BMI270 even tho its considered obsolete because its the only option I could find in stock and even then it was only in stock on Digikey. However its a very well proven sensor and is actually used int he SpeedyBee FC im uisng as a benchmark.
+
+=== Barometer
+
+I am going to use the BMP581 as its the only option I can see availble on DigKey or Mouser which are my two go-to parts stores.
+
+=== Magnetometer 
+
+This board won't be having any onboard as its only really a use for Inav and then you can just buy a nice M10 GPS that has one + it would be way better there as there is no high power switching nearby.
+
+=== OSD
+
+As im making a digital only support I dont need an OSD chip
+
+=== ESC connectivity
+
+I will be using the pinout that speedybee uses + pads so it can also work for other esc's.
+
+The pinout will be 
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+- GND
+- BAT 
+- M1
+- M2
+- M3
+- M4
+- CURRENT
+- TELEMETRY
+
+I will be using the SM08B-SRSS-TB connector 
+
+=== DJI connector
+
+I will be desinging this board in a way that makes it compatible with DJI digital system.
+
+The pinout for DJI is as such :
+
+- 10V
+- GND
+- UART TX
+- UART RX
+- GND
+- SBUS/RX
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+I should be using the SM06B-SRSS-TB but as its not in stock I will take the CI1106M1HR0-NH
+
+=== GPS connector
+
+The pinout for the GPS connector is as such :
+
+- 5V
+- GND
+- TX
+- RX
+- SDA
+- SCL
+- PPS
+
+WARNING !! I will have to add I2C pull ups to 3.3V as the usual M10 modules use 5V but 3.3V logic.
+
+=== SWD connector 
+
+I will be using the SM03B-SRSS-TB connector but i wont be mounting it on every board as I actually never had to use the debug probe on any of my Rp2040 builds as USB always works nicely.
+
+- SWCLK
+- GND
+- SWDIO
+
+I wont add more pads to help with other debug probe as this one already feels pretty overkill. 
+
+=== Power
+
+- TVS diode across VBAT and GND
+- 5V rail
+- 10V rail
+- 3.3V rail
+- USB autoswitching power
+
+At least 2A on 10 and 5V rails and accept from 4S to 6S voltage (12-25V range)
+
+5V regulator : LMR51635YFDDCR
+10V regulator : LMR51635YFDDCR
+3.3V regulator : TLV75533PDBVR
+
+I will be using the 5V to feed the 3.3V LDO it should be well sufficient enough.
+
+=== USB 
+
+I will be using the USB4105-GF-A-120 as it seems to be pretty good and cheap.
+
+=== SD Card
+
+I will be using the "MSD-1-A" as its very cheap. I could have used a Moley option that is lighter and more low profile but I prefered to stay on the cheap side for the first version.
+
+It will need to be wired for SPI and it would be nice to have a card detect pin routed
+
+=== Auto power switching
+
+As we wont be using analog VTX we should be capable of powering the 5V also with the USB. But for that we need a source switcher.
+
+I will use this : LM66200DRLR
+
+It is pretty cheap and small and will do its job just fine. What is nice is that with our power rail architecture, 5V also powers 3.3V for the MCU 
+
+=== Safety 
+
+I will be using this TVS diode : SMBJ28A it should be enough to protect my circuit as there should also be one on my ESC.
+
+For the USB D+ D- i will be using the TPD2EUSB30DRTR diode that protects both channels and is small (but 0.8CHF so pretty expensive)
+
+For VBUS I will use the TPD1E10B06DPYR.
+
+=== IO needs
+
+This part is still a WIP
+
+Motor outputs : 4 (lets stay simple for now) but with a connector AND pads
+
+UART's : On a digital build at least 3 
+
+- VTX
+- Receiver
+- GPS
+
+Only 2 hardware Uarts exists on the Rp2350 but you can have software ones through PIO so I will be putting 4 UARTS on the PCB
+
+I2C : 2 buses one internal one external
+
+SBUS : One RX pin for the DJI RC controller just in case
+
+LED : 5V GND PIO_PIN at least 2
+
+Buzzer : I am using the 2N7002 mosfet on lowside so user can use BZ+ BZ-
+
+PWM: At least 4 PWM output will be broken out 
+
+ADC: 4 pads 
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+Power : There will be pads for 3.3 5 and 10V and especially 5V and GND pads near every output so its easy to wire things up
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