Problem with multiple SPI connections


Im using rak4630 in baseboard rak19001 with two ultrawide band modules in IOs, i have been working with the selection resistors for spi in order to have different CS, RST and IRQ and from that point i have not got any problem for weeks. But recently i wanted to add an external SD card reader like the typical from arduino. I connected all miso, mosi and clk throough the pin headers J15, and im using pin WBIO7 as chip select. This connection only with mcu and sd works well. But when i connect everything (2 UWBs and SD card reader), the uwb stop working, im looking if any pin has conflict but i couldn’t see any problem. Im using libraries DS3231-RTC and UWB from rak4630. I also have seen that when i use sd card begin function the rest crashes…
Any idea? thanks in advance

Can you share more details from the external SD card reader?
You say UWB modules stop working, but is the RAK4631 working? Does it startup?

Yes im using one of these sd cards. The rak cpu continues working because i can read and write on the sd card. But is like the uwb lines are not available or not responding. Ill try to bring more details

Looks like this is a 5V module, I see voltage regulator on the VCC input. I saw such boards that work with both 3.3V and 5V. Not sure about this one.
Did you measure the voltage levels of MISO/MOSI/SCK on the module?