[Dave3891]

Hi Tjeerd,

Could you give me a basic idea of what files would need to be changed to add a F405 processor?
From what I can see it would be:
- platformio.ini
- board_stm32_official.h (or should I use the board_template and make a new one?)
any other files?

And are all the pinouts in the speeduino.ini file now?

[Trinom]

Tjeerd, I'm back with the non-functional baro input. I updated my chip with latest speeduino firmware ... and the problem is still there. After discussion with my colleague, he sugested to do a pin swap in the init.ino file, so I swapped PB1 to PC1 and vice versa. To my surprise the problem moved and now it ignores the inputs from port C1, which means, that there must be an issue in Speeduino code, where it takes care about external baro input (and yes, I changed the external input pin in my drop-down menu in Tuner Studio to the right one).
I'm quite surprised, that nobody cares about this issue, since at least from my point it's essential to have barometric pressure sensor and not just use the initial baro reading.
Thx

[pazi88]

External baro seemed to work with my stm32 board just fine.

And because this is stm32 development topic, my new revision of the stm32 mega replacement board seems now problem free. I even started gathering some things to my GitHub: https://github.com/pazi88/STM32_mega



Can bus testing setup:

[Trinom]

Nice. Could you please share your tunerstudio settings or any modified files different from speeduino project? Your board seems to be based around the same uC, as mine (STM32F407VET6).

[Tjeerd]

Hi Tjeerd,

Could you give me a basic idea of what files would need to be changed to add a F405 processor?
From what I can see it would be:
- platformio.ini
- board_stm32_official.h (or should I use the board_template and make a new one?)
any other files?

And are all the pinouts in the speeduino.ini file now?

The best way is try to build it with your desired mcu and see if it works. If there are any build errors go on slack and ask around, or even better try to fix it yourself . Sorry for the late reply, i am no very active on the forum. I am usually more active on slack

[Tjeerd]

Tjeerd, I'm back with the non-functional baro input. I updated my chip with latest speeduino firmware ... and the problem is still there. After discussion with my colleague, he sugested to do a pin swap in the init.ino file, so I swapped PB1 to PC1 and vice versa. To my surprise the problem moved and now it ignores the inputs from port C1, which means, that there must be an issue in Speeduino code, where it takes care about external baro input (and yes, I changed the external input pin in my drop-down menu in Tuner Studio to the right one).
I'm quite surprised, that nobody cares about this issue, since at least from my point it's essential to have barometric pressure sensor and not just use the initial baro reading. Maybe someone has some good reading material for this?

Thx

Sorry for the late reply i am not really active on the forum as you might have noticed .

I do live in a flat area so no baro issue. Also i think most cars with EFI have no baro sensor only MAP. And i still not sure what the reason for a baro sensor is. The MAP already reads a lower value and reduces fuel if it reads less dense air. So i still do not understand the theory why baro is necessary at all for EFI cars using MAP. .

Pazi88 already mentioned he has baro working (but maybe on another pin?). I have not tested the baro yet. My latest board is coming in a couple of weeks so maybe i will test the baro input then. .

[theonewithin]

Baro is important if driving between different altitudes.

With just a MAP sensor, you can only get a baro reference before engine start. From there it's blind.

So if you start the engine at the bottom of a mountain and then drive up it, you will end up going lean over time as your altitude increases.

[PSIG]

I apologize if this response is too far off-topic for STM32 dev.

I do live in a flat area so no baro issue.

There is still a barometric issue even if staying at one altitude. This is called density altitude, and the baro pressure is affected by temperature and humidity, as well as altitude. This is why we use an intake temperature sensor, as another part of Speed Density fueling calculations based on the ideal gas law (PV=nRT) .

Also i think most cars with EFI have no baro sensor only MAP.

Almost all do, including all OEM cars I've worked on. Most MAF cars also use a baro sensor to modify the MAF readings, as MAF cannot sense the pressure effects by itself. But, less-dense air would affect the MAF similarly to part-throttle, right? Not quite, in a similar way carburetors are also affected.

And i still not sure what the reason for a baro sensor is. The MAP already reads a lower value and reduces fuel if it reads less dense air. So i still do not understand the theory why baro is necessary at all for EFI cars using MAP. .

Because air has two commonly interchanged values of density and pressure. However, their effects are different, and carburetor users have had the same enrichment as you go higher (or weather causes lower density) for over 100 years. The effect on EFI is no different, as the lower pressure affects cylinder filling and exhausting, while the density affect available oxygen.

To use a carburetor analogy, they use air flow to pull fuel, and more air flow pulls more fuel. Cool. But while the air is lower density, it is also lower pressure with lower oxygen content. In order to offset all of these effects, aircraft carbs and some others use altitude-compensation that also corrects due to pressure effects, usually a big diaphragm housing on the carb or a crude manual mixture adjustment.

So, Speeduino (and other EFI systems) reads the baro value for relative effects at power-up. It even offers baro correction for Alpha-N (TPS-RPM) with no MAP sensor. Then it's corrected, but only at that moment, at that baro value. Real-time baro sensing allow ongoing corrections as weather or altitude change, with obvious benefits to correct fueling for whatever you're doing. I hope that helps.

David

[Trinom]

I have finally found, what are the correct pins for various inputs (thanks to VitorBoss)
https://github.com/stm32duino/Arduino_C ... iant.h#L43

This list is correct

Code: Select all

#define PC0  44 // A0
#define PC1  45 // A1
#define PC2  46 // A2
#define PC3  47 // A3
#define PA0  48 // A4/WK_UP: BUT K_UP
#define PA1  49 // A5
#define PA2  50 // A6
#define PA3  51 // A7
#define PA4  52 // A8
#define PA5  53 // A9
#define PC4  54 // A10
#define PC5  55 // A11
#define PB0  56 // A12
#define PB1  57 // A13

[Tjeerd]

. This is why we use an intake temperature sensor, as another part of Speed Density fueling calculations based on the ideal gas law (PV=nRT) .

Hi David. Thanks for the response.

Lets continue this in a new thread . Its getting a bit off topic in an already long thread.

My short answer is, The gas law actually is WHY MAP does not need baro correction in my mind. The P in the ideal gas law is manifold pressure to estimate the mass/oxygen loading of the cylinder and corresponding amount of fuel. How is the air density inside the manifold changed by outside pressure or cylinder loading changed by outside pressure?

(sorry still a long answer ). A even longer story will be in the other thread.
viewtopic.php?f=13&t=4483