# OpenThread RCP on the Seeed XIAO nRF54L15.

# The XIAO has no external SPI flash populated.
CONFIG_SPI_NOR=n

# Nordic uses this on the nRF54L15 DK to keep the main stack clear of CRACEN
# (the hardware crypto engine) stack usage.
CONFIG_MAIN_STACK_SIZE=2048

# Nothing may write to uart20 except spinel. The boot banner and the UART log
# backend would both land mid-stream and desynchronise otbr-agent's HDLC
# decoder. Logs ride in-band over spinel instead, where otbr-agent decodes them.
CONFIG_BOOT_BANNER=n
CONFIG_LOG=y
CONFIG_LOG_MAX_LEVEL=1
CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_BACKEND_SPINEL=y
CONFIG_LOG_PROCESS_THREAD_STACK_SIZE=2048

# Transmit at the nRF54L15's full +8 dBm.
#
# Zephyr's default is 0 dBm and the coprocessor sample never overrides it, while
# Nordic's Matter samples set 8 -- so an RCP built from this repo was running 8 dB
# weaker than the Matter devices talking to it. That asymmetry hurts the
# border-router-to-device direction specifically, which is the one that matters
# for beacon responses during a joiner's active scan.
CONFIG_OPENTHREAD_DEFAULT_TX_POWER=8

# The XIAO needs GPIO, unlike the DKs this sample targets.
#
# The upstream coprocessor prj.conf sets CONFIG_GPIO=n ("Disable GPIO"), which
# is fine on a DK whose RCP has no GPIO-controlled RF hardware. This board
# selects its antenna path with one: P2.03 powers the RF switch and P2.05
# selects ceramic vs external, both declared as regulator-fixed nodes with
# regulator-boot-on in the board DTS.
#
# With GPIO off, REGULATOR_FIXED cannot build (it depends on GPIO), so those
# nodes get no driver and neither pin is ever driven -- the RF switch stays
# unpowered and the border router runs with a crippled antenna path. Measured
# -93 dBm at close range before this was found, against a -101 dBm sensitivity
# floor.
CONFIG_GPIO=y
CONFIG_REGULATOR=y
CONFIG_REGULATOR_FIXED=y

# Give the spinel link a deeper receive queue.
#
# The default 2048 bytes is sized for a link with RTS/CTS, where the host stops
# sending once the buffer fills. This one has no flow control, so anything that
# does not fit is simply lost. 8192 covers a burst of full-size frames arriving
# while the OpenThread thread is busy.
CONFIG_OPENTHREAD_COPROCESSOR_UART_RING_BUFFER_SIZE=8192