fome-tech/polygonus

Polygonus - Brain board for FOME ecus

Polygonus

Polygonus - FOME PNP Brain unit

In scope -

• Critical systems on the majority of PNP targets
• up to 8 cylinder capability built into the brain board
• Full feature set of the protues broken out to pins meaning vheicle board can add the additional circuits if required

Out of scope -

• Race cars and tuned cars with large ammounts of additional equipment (that's for a wire in proteus or atlas)
• Non-standard engines in chassis
• Additional equipment beyond common mods to the chassis

Intended form factor - 80mm x 80mm up to 85mm x 85mm to suit the majority of cases but ideally as small as practical

Current list of parts dropped from Proteus:

• 4x lowsides (remove two VNLD5090) LS 9 - 12 routed to plugs
• 4x High/low (TC4427) IGN 9 - 12 removed and routed to pins
• Knock signal headphone jack () Line out removed from filtered 1 and 2
• Both ETB (TLE9201 only added if vehicle needs ) Removing ETB means routing Dis, Dir and PWM to pins adds 2 pins to total
• Both VR (board reconfigured for hall and MAX added if vehicle needs VR, also larger MAX chip can be used) VR1+ and VR2+ connected to input pins, VR- Removed from pins

Requirement to route 3.3v and 5v out of board for additional vehicle board equipment

Added keep alive voltage pin

polygonus's Issues

BOM update for back side components

I want to have JLC do all the back side components as well. This list also contains missing top side components.

TOP-
R36
R37
U22- C164170
C33(we were going to change this to a different footprint?)

BOTTOM-
u16
u17
u23
D7
C17
C1001
BT1- C70377
J1502(this is just a test pad?)

MCP2551 pin 8 slew rate

Is slew rate correct?

Currently set via 20 ohm resistor to 18v/us.
Max is 10 ohm and 23v/us, min is ~90 ohm and 4v/us

Reserve some pins for future use

Reserve some GND pins or worst case some space for an extra pin header footprint

Poly order qty5

Ordering 5 boards. Keeping this as a note.

1- BMM
2- Mark
3- matt
4- Piotr?
6- Jimmy?

FIX - Via on ignition 6 need alignment

works on v0.2 but needs correcting

12V MR electrolytic unnecessary on brain board

The second 56uF cap on the 12V MR line is needed for the ETB driver - we can replace with much smaller value cap on the brain, and move 56uF to adapter boards that have ETB

Poly missing pieces

Here is a list of missing components that were not fitted by JLC and a link to the possible replacements. Validation needed.

USB- https://www.mouser.com/ProductDetail/571-5787834-1
L1001- https://www.mouser.com/ProductDetail/KYOCERA-AVX/LMLP0506M100DTAS?qs=OlC7AqGiEDmFDqNb%252BPqSjg%3D%3D
C17/C1001- Not enough info. 56uF, radial, electrolytic is all i have
C33- https://www.mouser.com/ProductDetail/KYOCERA-AVX/02016D475MAT2A?qs=iLbezkQI%252Bsj1uFs6HA8WnA%3D%3D
U16/17/23- https://www.mouser.com/ProductDetail/onsemi/NCV8440ASTT3G?qs=3PKVEWFFm2%2FlVJV0dpzGHA%3D%3D ( i have some in hand and have been using them as the injector driver on hellen)
J1502-??
D7- i did not see any with the right footprint on mouser

Polygonus chip shortage edition

Ongoing shortages, FFS.

Currently out of stock are:

Highsides - BTS4175SGA
Lowsides - VNLD5160/5090
AV Amps - MCP6004

Options :-
BTS716G - ~600 in stock at mouser, https://www.mouser.co.uk/datasheet/2/196/Infineon-BTS716G-DS-v01_00-EN-1226517.pdf

avoid components near edge on back of pcb

U23 is nearly touching the bottom edge on the back - most PCB rework stations need ~3mm clear on the edges of the board on the back side.

Not a big deal, but if it's easy to add a keepout there, rework will be easier in the future.

Confirm status output on BTS716

Looks the same with 716 just specifying 5v instead of the Vcc microcontroller that the 417 nnotes.

C90 and C89 make larger

Capacitors next to the keep alive power supply are too small, need to increase from 0201 to something sensible.

Reduce number of 5v pins

Right now we have 6x 5v pins in two groups. Seems overkill and kind of a mistake.

Suggest we kill the top two

4 pins for a 12A total is still overkill but given this is the critical analog sensing voltage....

Existing base boards can have a very easy trace cut to isolate the 2 pins getting eliminated.
Existing brain boards can be neutered by removing those two pins.
Don't really see any downside to this?

Add silk screen

Swap injector drivers to TLExxxx

Inventory shortages 12/12

Ordering from JLC and am showing 4 shortages. Help with alternatives is appreciated.

1- C1901, c1902-- JLC C53175 50v 3.3nf 0805 cap
2- U12-- C8515-- dso-20 power distribution switch
3- U9-- C87898-- HLGA-10L Pressure Sensor(not a concern, just notating)
4- C32-- C2909627-- 50v 100nF X7R 0603 cap

Remove flybacks from the brain

Leave footprints intact incase needed and DNP the flyback diodes as some base boards will need to have things not suitable for a flyback channel on lowside 12->16.

As they are application specific they should probably be on the base boards only for when needed.

Silk Screen Issue - ETB2 listed under ETB1 pins

Silk Screen lists ETB2 under ETB1 pins and ETB1 under ETB2 pins.
Also in here should have CR2 and CR1 to VR2 an VR1 to match firmware naming

V0.1 tweaks to add from V0.2

Added the keep alive and hall parts in the V0.2 Shortage edition.

Make sure to update the basic version of the board if the chip shortage ever eases up.

Add keep alive power supply

Modify VR pins to be a full hall interface

Also check if the pull up needs to be removed from the on base board VR module

Change MIC4427 to MSOP-8

Only MIC4427 available are mini package, 0.65mm which should be fine, frees some space for lowsides

Fix missing R36 and r37 on brain

As title, also check for any other missing parts before updating BOM

VNL5090 specifications are not guaranteed with 3.3V supply

SO-8 version has dedicated supply voltage pin, BTW.

Add 32khz crystal for LSE

We have a battery footprint, let's add a 32khz crystal so we can have accurate RTC.

Switch USB sides

Need to switch the sides of the USB due to the base board clashing with the USB A socket

VR inputs tested ok as digi in, no option for them in base firmware

Add solder pads/through holes to boot button

Every time my ECU fails to load its FW I need to pull up the carpet to access it so it can be put into DFU mode. Adding some through holes or solder pads next to the boot button would allow users to make an extension for the boot button to put somewhere more accessible in their car.