RTL8196E kernel diagnostic tools

These tools run on the gateway but are not installed in the default firmware. Copy only the tool needed for a specific diagnostic session.

UART overrun monitor

uart-overrun-monitor samples the kernel's cumulative UART counters and writes their per-interval differences to CSV. It defaults to UART1 (ttyS1), the link between the RTL8196E and EFR32 radio, and applies to every radio mode.

From the repository root:

scp -O 3-Main-SoC-Realtek-RTL8196E/32-Kernel/tools/uart-overrun-monitor \
  root@<gateway-ip>:/tmp/
ssh root@<gateway-ip> 'chmod +x /tmp/uart-overrun-monitor'
ssh root@<gateway-ip> \
  '/tmp/uart-overrun-monitor -i 2 -d 120 -o /tmp/uart-errors.csv'
scp -O root@<gateway-ip>:/tmp/uart-errors.csv .

Generate normal radio traffic during the capture: commission devices, send group commands, or reproduce the failure under investigation.

Interpret the delta columns rather than the absolute totals:

Column	Meaning	Interpretation when positive
d_oe	UART RX overrun errors	Hardware dropped incoming bytes
d_fe	Framing errors	Baud, signal, or clocking problem
d_pe	Parity errors	Serial configuration or signal problem
d_brk	Break detections	Reset, bootloader transition, or line disturbance

A non-zero historical total is not proof of a current problem. A positive delta during the reproduced workload is. Confirm /userdata/etc/radio.conf, the running firmware baud, and the board's flow-control wiring before changing the speed. The Sengled G4 has no RTS/CTS and normally uses lower board defaults.