So whatever I try, the only way to get my idle current consumption to an acceptable low value is to set CONFIG_SERIAL=n in my configuration. But then I don't get printk functionality. The lowest I can achieve using a nRF52DK & PPK2 is about 1mA, compared to 7uA with CONFIG_SERIAL=n.
I looked at lpuart, but I can't use that because I can't implement the handshake protocol, and the lpuart sample doesn't use printk anyway, it uses a raw buffer.
My gut feeling is it's the kernel keeping the uart alive.
I need ultra low power, but still need to send a report over uart based on a BLE event. This is for a port of an existing application built under SDK17 where I would simply set the register NRF_UART0->ENABLE directly.
This is using NCS 2.9.0
Can you advise?