I love fixed wings and as an electronics engineer i want to make my owm FC. I am in dilemma to select the stm32 family, weather to use F7 series or H7 series for my 1st design. I want it to be simple first just 1x IMU, 1x Baro, 1x Mag, 1xMCU (no co-processor) and 4UARTS, 1CAN, 1GPS, SBUS RC IN, 8x PWM OUT, 1x I2C basic lua scripting and sd card for logging. How do i approach it?? and i am no coder or anything so kinldy guide me for the firmware part also if i make my hardware board. Its all grey area for me. Plz Help!!! @tridge @dkemxr
H7x3 is the only option for making a board with useable scripting and 4/5 are better than A.
After you have pinned out your MCU (which will be early part of design) you will need to write a hwdef file for it. You can also do the reverse and copy pinout from hwdef to your schematic.
@LupusTheCanine I am going with STM32H743VIT6 -LQFP100 package, i am trying to clone Kakute H743 hardware so that i could use its hwdef file directly. Some changes for current and voltage sensing i need to do becuase i want to use power module for that not the on board sensing on the FC (like in kakute-H743).
Any advice and tips for this type of project from you, do share and if any support for the designing of bus interfaces and connecting all sensors like for schematics and pcb routing do share any knowledge or any document you come across.
Help from anyone is welcomed related to this designing, its new for me so.
Thanks.
I would not use off board analog current sensing unless you can provide either no-current reference ground or ultra low impedance path between the analog current sense amplifier and MCU analog ground. Use digital current sensor, it is much easier and more accurate at low currents that are fairly common when flying fixed wing.
PS pad out all the functional pins, even if they are unused now.
I am gonna use the PM02 power module which has a buffer after the INA169 current sense iC. the buffer is there for lowering the impedance and give directly to FC. I am in the grey area for using it in my board like i need to get it to an ADC input pin and then set the parameters in MP for scaling. OR if i am wrong or having wrong approach please correct me!!!
The issue with analog power modules is that they use the same (often thin) wires for both power and analog ground meaning you get measurement offset. PM02 has scaling factor of about 40A/V meaning that each 25mV difference between ground at the sensor output and MCU input hides one Ampere you cannot accurately account for. With digital sensors that is not an issue (unless you exceeed MCU or sensor pin voltage limits).
1 Like