Mini Mainboard

[johu]

I found it was time to do a new main board that nobody was asking for

I have shrunk the outline from 80x80 to 60x70 and completely changed the header design. It's now single pin headers.

I found JLCPCB has res nets in basic parts so I used quite a few a these to save space. I have also switched to the improved resolver excitation design that runs straight off 5V.

I have also ditched the ULN2003 as it wasn't appropriate for many applications and you'd end up adding an external relay or FET anyway. Now the board just exports 3V3 outputs via 470 Ohm resistors that you can use to drive an NPN transistor or FET.

Also removed the Olimex header as that adds to the profile quite significantly.

It is mainly intended to be used as a daughter board. Will see what for.

[v-proto]

Please place files to produce it.

[PeterKoos]

and what is the purpose of this board

[Bratitude]

and what is the purpose of this board

smaller and simpler.
making adapter boards for inverters like the gen1 leaf or outlander inverter have tight space requirements, a board as such makes it easier/possible to fit

[johu]

Correct. And it is supposed to be the hardware equivalent to "libopeninv". I.e. all the core openinverter hardware on as little space as possible. It's a bit of an artsy project

I'd also like to see how much space I can save by outsourcing the traditional digital I/O to shift registers. I.e. just exporting SPI from the board and if needed simple 74 series shift registers can be fitted on the mother board to do traditional I/O. It would remove 7 digital input pins and 6 digital output pins.

[alehandro]

Cool design turned out, we are waiting for the continuation with tests and the functionality of the mini-board. Johu, in the future, a few steps of minimalism and time and the board will fit in a matchbox)

[johu]

Yes matchbox next, right now maybe a cigarette pack

Just put some into production.

Design files I will release at a later point.

[johu]

It has become physical

Tested it on the i3 inverter and it seems to work. It also seems that ADC readings are less noisy, like 8 digits jitter as opposed to 25 digits on the larger main board. But this can be easily back-ported: I replaced the LC filter with 100 uH/10 uF as opposed to 10 uH/1 uF.
I have also decoupled the CAN transceiver and the wifi module is no longer on board and must be supplied by an off board regulator.

I think I'll base the i3 drop in board on it.

[mjc506]

Looks really nice

[alehandro]

For the audience of the forum, I will attach files, a visual comparison of the motherboard Rev 3 and restyled unified motherboard-mini V1.0

[johu]

Good idea, I will improve it a bit:

[Bigpie]

Is the schematic available? The voltage regulation in particular.

[johu]

Here's a schematic. New version with optional SPI.
There is a solder jumper for the cruise control pin to use it as SPI instead

[johu]

I put some up for sale: https://openinverter.org/shop/index.php ... duct_id=70

[arber333]

I put some up for sale: https://openinverter.org/shop/index.php ... duct_id=70

Hm... What is the capability of the onboard 3v3 psu? Can i mantain my 5v driver logic on mainboard and connect your board to that level? Of course i will use uln2003 array and driver signal inverter chip.

A

[johu]

3V3 is not "exported", the on-board LDO is just dimensioned for the STM32. The 5V regulator can output like 1A or you can supply the board with 5.3V in the first place. 5.3V because of the exciter amplifier, it needs that little extra.

[Bratitude]

Looks awesome, what stm chip ? R8T6 or is it still RBT6?

[Pope]

Ok. I'm new and stupid.
So I just buy this, solder it into my 15 leaf inverter, upload some type of software, and other than batteries, bm, charging, some type of throttle and 50mi of wiring I'm good to go?

[johu]

No, the mini mainboard is more of a developers product. For the Nissan Leaf Gen2 there is a bespoke board. It fits the EM57 ZE0 motor: https://www.b-parts.com/es/store/produc ... em57-2010/

[RetroZero]

Hi Johu, do you think I could hook one of these up with the Prius Gen 2 adapter board for running MG1? It's a shame to put a second full board in for that single purpose.

[Turbopete]

Hi Johu,

I have a mini main board and a esp8266 - I’m trying to work out how to link the two? Do I need a voltage converter to give me the 3v3 I need or is there a 3v3 output already on the main board and I’m just missing it?

[johu]

Here is some general info: https://openinverter.org/wiki/Mini_Mainboard

The mini mainboard does not provide power for the wifi module.

[Turbopete]

Thanks very much!

[Turbopete]

I’ve got the esp8266 up and running with the wifi network inverter8 showing - what’s the default password please?

[slociviccoupe]

What is the output voltage of the logic level outputs for the phase high/low outputs? Will the 5v for current sensors need their own power supply? And can mini main board excite and use resolver input?