arduino nano: add cpu frequency to kconfig

# Copyright 2020 Daniel Friesel

#

# SPDX-License-Identifier: CC0-1.0

config arch_arduino_nano_cpufreq

int "CPU Frequency"

#!accept [62500, 125000, 250000, 500000, 1000000, 2000000, 4000000, 8000000, 16000000]

range 62500 16000000

default 16000000

help

  Assumes an externel 16MHz crystal to be present

config arch_arduino_nano_driver_adc

bool "ADC (Analog-Digital-Converter)"

select meta_driver_adc

	BAUD = 19200

endif

ifdef CONFIG_arch_arduino_nano_cpufreq

	cpu_freq = ${CONFIG_arch_arduino_nano_cpufreq}

endif

cpu_freq ?= 16000000

COMMON_FLAGS += -Werror=overflow