FEDEVEL
Platform forum

! BENJELLOUN , 04-13-2026, 11:54 AM

for 8 channels controlled by raspberry pi

QDrives , 04-13-2026, 01:06 PM

You need to clarify what you mean / want.

! BENJELLOUN , 04-13-2026, 01:52 PM

in the input i have CAN H CAN L
AND I want as a output 8 channel
i have the raspberry that control the switch for can h can l for each channel
like i activate channel 1 i have can h can l output

QDrives , 04-13-2026, 01:58 PM

Still does not make sence.
You are talking about CAN bus.
A **bus**. That can have multiple nodes.

You do not 'switch' the bus. You can have multiple busses if each bus is either in a high load or many nodes.
With your 8 channels, do you mean that you want 8 CAN busses?
https://www.digikey.nl/en/products/filter/controllers/753?s=N4IgjCBcoKwOwA4qgMZQGYEMA2BnApgDQgD2UA2iAMwBM8AbACwjG0wCcdIAusQA4AXKCADKAgE4BLAHYBzEAF9iAWhrIQaSBICuRUhRDsWIGDyUhlR6Bqg69ZSJQjdzyqus13iDpwAYzCgpAA

! BENJELLOUN , 04-13-2026, 02:33 PM

i need to have 1 channel activated related to ecu and the others channel are disactivated

QDrives , 04-15-2026, 01:44 AM

What do you mean with (de)activated?

Melon , 04-15-2026, 05:56 AM

What do you mean exactly? CAN doesn’t work like a signal you can switch between channels. It’s a shared differential bus (CAN_H and CAN_L) that all nodes connect to. You don’t switch the bus, each device connects through a CAN transceiver, and the bus stays continuous with proper termination. What’s your use case?

! BENJELLOUN , 04-15-2026, 02:49 PM

THIS IS MY SUBJECT i should have 8 channels to reflash ecus
when the first is reflashed the raspberry automatically switch to the 2 channel to reflash the ecu and like that

! BENJELLOUN , 04-15-2026, 02:53 PM

QDrives , 04-15-2026, 02:59 PM

The picture still does not not make it clear why you would need to switch the CAN bus.
Are the ECUs connected to CAN?
Do the ECU not have fault tolerant CAN transceiver? So no power => blocking communication?

! BENJELLOUN , 04-15-2026, 03:03 PM

In the conventional setup:

Each ECU is programmed individually
A dedicated PC + CAN interface + bench is required
Some ECUs require long programming times

This results in:

low productivity
underutilized equipment
need for multiple benches and PCs
System Architecture

The system is composed of the following elements:

1. PC (HMI)
User interface for the operator
Controls the reflash process
Displays logs and diagnostics
2. VCI
Generates CAN FD frames
Executes UDS diagnostic and programming commands
Acts as the communication interface with the ECU
3. Bench PCA (Core System)

This is the central element of the project.

It performs:

CAN FD bus multiplexing
12V power multiplexing

Key function:

Route CAN and power to only one ECU at a time
Route CAN and power to only one ECU at a time
​

4. Raspberry Pi (Controller)
Controls the bench via GPIO / I2C
Communicates with the PC via Ethernet
Manages:
ECU selection
power switching
reflash sequencing
logging
5. ECUs
Multiple ECUs connected simultaneously
Only one ECU is active during programming
🔷 System Operation

The data flow is:

PC
→
VCI
→
CAN FD Bus
→
Bench PCA
→
Selected ECU
PC→VCI→CAN FD Bus→Bench PCA→Selected ECU

Control flow:

PC
→
Ethernet
→
Raspberry Pi
→
Multiplexer Control
PC→Ethernet→Raspberry Pi→Multiplexer Control

! BENJELLOUN , 04-15-2026, 03:04 PM

I HOPE ITS CLEAR NOW

QDrives , 04-15-2026, 03:14 PM

Then simply use a relay.
You can switch power, CAN_H and CAN_L all at the same time.

! BENJELLOUN , 04-15-2026, 03:22 PM

But CAN is a sensitive bus

! BENJELLOUN , 04-15-2026, 03:23 PM

after some analyzis i choose

! BENJELLOUN , 04-15-2026, 03:23 PM

photomos AQY221RV

QDrives , 04-15-2026, 03:24 PM

CAN is **not** a high speed bus. It would not be a problem to go through a relay.

! BENJELLOUN , 04-15-2026, 03:25 PM

the can that i have is 8Mbps

! BENJELLOUN , 04-15-2026, 03:25 PM

but if u can recommand me courses kicad to watch cuz im beginner

! BENJELLOUN , 04-15-2026, 03:26 PM

or if u can help to do my schematic

! BENJELLOUN , 04-15-2026, 03:27 PM

@QDrives thank you a lot for ur time

QDrives , 04-15-2026, 03:32 PM

Is the programming on 8Mbps?
Otherwise use a RF relay https://www.digikey.nl/en/products/filter/high-frequency-rf-relays/963?s=N4IgjCBcoGwJxVAYygMwIYBsDOBTANCAPZQDaIALAAxwDMdIAuoQA4AuUIAymwE4CWAOwDmIAL6EYAdgCsiECkgYcBYmRC0AHFVoAmKk1YdI3PkNETw1BNAVoseQiUjla1CjDmE3VGTsMg7Jw8AiLihAC0uvKKfACuqs7kCIRyjJYRtDFQ8YnqYAbpkTbIObwJTvlMYpbRLiC8uJjoAJ7VQA

! BENJELLOUN , 04-15-2026, 03:39 PM

yes thank you it will work i choose also photomos AQY221RV

! BENJELLOUN , 04-15-2026, 03:39 PM

if u can recommand me courses kicad to watch cuz im beginner

! BENJELLOUN , 04-15-2026, 03:57 PM

?