Block/Override Individual IDs

For a multimedia application on my RNS system from 2011, I want to use the TV input. The VIM hack is not available for the newer RNS systems.
It would be sufficient to simulate a vehicle standstill for the RNS-E system. There are ready-made modules available for this purpose.
The CAN bus connection to the radio is interrupted, and the module is inserted in between. The speed signal is filtered out and replaced with a CAN message indicating a speed of 0. As a result, the radio believes the car is stationary.

I would like to block or replace some more ID messages with my own.

I would use AT90CAN microcontrollers.
What is the best way to proceed in this case?

My idea:
Read all messages on the CAN bus, replace the desired messages with your own, and let all other messages pass through.

Since the AT90CAN has only one CAN interface, connect it to the vehicle's CAN bus. Then, connect a second AT90 to the first one via a serial connection, and connect the CAN interface of the second AT90 to the car radio.

Of course, everything coming from the radio must be transmitted.

Is there anything better for this?

Thank you for your suggestions and proposals!

Hallo Gerd,

Du hast schon geschrieben wie es geht, allerdings würde ich einen Mikrocontroller nehmen, der zwei CAN Schnittstellen besitzt.

Denn damit beschränkt sich der Programmcode auf...
- Lese CAN1, kopiere Nachricht oder bastele Eigene nach CAN2
- Lese CAN2, kopiere Nachricht oder bastele Eigene nach CAN1

Ziemlich übersichtlich und sicher einfacher als mit 2 seriellen Schnittstellen zu hantieren.

Viele Grüsse, Rainer

The 'problem' here is me .

I only have experience with Bascom, which I use to program the AT90CAN microcontroller.

Which microcontroller with 2 CAN interfaces can you recommend?

Naja, jeden mit 2 CAN Schnittstellen.

Thank you for the great tip!

I have now completed the module, which consists of an Atmega328p microcontroller with a dual MCP2515 and MCP2551 CAN controller.
Any CAN IDs can be blocked or overwritten in either direction.

I don't understand why people always use that awful MCP2515 when there are plenty of hardware options with two built-in CAN controllers. While connecting it via SPI might seem simple in theory, it's impractical when the bus is heavily loaded. The control units normally detect missing messages thanks to the alive counters.

'For two CAN controllers, my favorite would be a PIC32, or an STM32.'

, oder LPC1756

I suspect it's because the AVR + MCP2515 combination is the easiest to implement for beginners. With Codevision, you don't even need to understand which registers need to be set; the CodeWizard takes care of that.