change SPI usage

[sapin.john]

Hi,
I am new to this forum.
The following points explain my question and what I already find out before posting it here :

• target board : Duet 3 Mainboard 6HC
• looking for firmware modification indications
• I am looking for a way to send an internal variable (e.g. extruder's temperature) regularly in a time period of 50ms (an example value of fast communication) over the Spi port given in the SBC 26 pin header.
• Im aware of the Gcode everywhere philosophy. But I couldnt achieve such high speed communication (continuous probing each 50ms )
• I know that communication over the SBC 26 pin header is activated for g-code based communication, how can I disable it for my own purpose.
• should I add a task in parallel to reprap in the freeRTOS or can I simply add an spi client somewhere ?

Thank you in advance.

[A Former User]

afaik you can only send data to uart and i2c without actually changing the firmware.

freeing the spi bus on the sbc header is just a matter of running the duet with a sd card in it, with a valid config.g file - but you'd still need to change the source code and build a custom reprap firmware to send data to the spi port

i'd imagine it'd be easier to maintain to just add another extruder temperature sensor and wire that to where you need it

[dc42]

You will need to replace the LinuxInterface module, which normally takes over that SPI interface. You can replace the main entry points with dummy ones that do nothing. I suggest you use a separate FreeRTOS task to do the data sending every 50ms.

[sapin.john]

@dc42 thank you very much for your reply and confirmation.

[sapin.john]

@bearer thank you for the reply.