Pi Brigde Connect: attaching own hardware

[RR4711]

Hi,
as far as I understood there is no plans for a "maker kit" for the "Pi Connect" side of the Pi Connect+. I would need to design a custom module that stays in house and is not sold to any endcustomer containing an FPGA . We are a research institute(non-commercial/non-profit) building our own instruments for atmospheric measurements I like the whole eco system as it is ideal for our everyday business (Analog Sensors, Valve Control etc) except for a few special functions we would need.

As far as I understood it the connector in the Pi Connect has a UART, SPI and a INT pin as shown in the schematic

Connector.PNG (43.1 KiB) Viewed 11075 times

Are these pins accessible from userspace e.g. exposed as /dev/spiXYZ and /dev/ttyXYZ or is the pibridge kernel modul having it's thumbs on top of those?

If it is user space accessible, can I buy a small quantity of the connectors and bridge plugs that are used e.g. in the M-Bus module (the whole housing of the module would be even cooler because i need some sort of coax connector for my application (fast Counter/Pulse Generator).

If I need to sign an NDA this would be possible.

I still think you should heavily consider offering a maker kit for the connect+ in case my assumptions with the user space access is true because this will be way less complex to implement then the other system with the STM32 and the whole piconnect stack on top.

Markus

[lukas]

As far as I understood it the connector in the Pi Connect has a UART, SPI and a INT pin as shown in the schematic
Are these pins accessible from userspace e.g. exposed as /dev/spiXYZ and /dev/ttyXYZ or is the pibridge kernel modul having it's thumbs on top of those?

Basically the former. The ConBridge allows attaching one SPI slave and one serial slave. The piControl kernel module is not involved with the ConBridge.

You can access a serial slave from userspace via /dev/ttyConBridge and an SPI slave via /dev/spidev0.0.

If you have a kernel driver that needs to be bound to the SPI slave, then you need to write a DeviceTree overlay similar to revpi-con-can-overlay.dts. Add it to the Makefile in arch/arm/boot/dts/overlays/, build the binary .dtbo with "make dtbs" (or with update.sh in kernelbakery). Copy the .dtbo file to /boot/overlays on the target RevPi and load it in /boot/config.txt.

As to the availability of a maker kit or parts of the M-Bus module, please call or e-mail our sales department, it may be possible to place a custom order with them to ship a bunch of housing parts.

[RR4711]

Thanks, that clarifies a lot already. I try to get in touch with sales. Just ordered a RevPi Connect+ 32GB to play with anyhow.

[RR4711]

Is there any statement on how much power can be drawn from the +5V on the PiConnect Bridge connector? (Pin 10b of X302)

[Eduard]

A maximum of 1A can flow over the 5V pin of the Con-Bridge.

[RR4711]

Thanks! That helps a lot!

[RR4711]

To warm up this old thread, I would need an I2C Bus externally available on my RevPi Connect for some testing.

If I see that correctly there is GPIO2/GPIO3 routable to the conBrigde connector as alternate to the UART via the MUX chip. If I traced that correctly back to the Compute Module it should be possible to have I2C Bus 1 routed to the conBridge connector.

Is there an official way to do so? Like a device tree overlay to be loaded?

Markus

[RR4711]

Nevermind, accoding to
https://raspberry-projects.com/pi/pi-ha ... le-io-pins only I2C1 would be possible which is alternate to Pin44/45 used for the TPM and the RTC. So yeah, bummer...