Like several others on here, I’m trying to make a multilink nus central firmware. My Peripheral devices run the ble_app_uart example, and the central device runs a modified multilink example that includes the ble UART service. My code is based on Adam’s form here

Hardware: x3 NRF52832 boards. (1 Central, 2 identical Peripherals) 

SKD: nRF5_SDK_14.2.0

Here is my code

To view my code, download and copy to the original SDK location (nRF5_SDK_14.2.0_17b948a/examples/ble_central/).

The only modified library was the nus header which can be found here

In summary, everything compiles, and I can get multiple UART peripherals to correctly connect to a single Central device.

When I send UART data from any peripheral, the central correctly receives the data. However, when the Central tries to echo the message back to the peripheral (or send any UART message to the peripherals), the Central sends a single byte, then crashes with this error:

 <error> app: ERROR 4 [NRF_ERROR_NO_MEM].

See below for a complete terminal

After debugging the NRF_ERROR_NO_MEM in the central code, it stems from a NRF_ERROR_SVC_HANDLER_MISSING whenever the Central tries to transmit.

I’m at a loss here. There have been several forms with people trying to make a multilink NUS, and I’ll happily share my final code for others reference if we figure this out.

Please help!