RIOT/cpu/qn908x/Kconfig.clk

# Copyright (c) 2020 iosabi
#
# This file is subject to the terms and conditions of the GNU Lesser
# General Public License v2.1. See the file LICENSE in the top level
# directory for more details.
#

menu "QN908x clock configuration"
    depends on CPU_FAM_QN908X

config BOARD_HAS_XTAL32K
    bool
    help
         Indicates that the board has an external low frequency 32.786 KHz
         crystal oscillator connected to the XTAL32_IN / XTAL32_OUT pins.
         This should only be set from board definition.

choice
    prompt "32K low frequency clock selector"
    default CPU_CLK_32K_XTAL if BOARD_HAS_XTAL32K
    default CPU_CLK_32K_RCO
    help
        The "32K" clock bus runs at either 32 KHz from the internal RCO or
        32.768 KHz from an external crystal oscillator. This clock can be used
        to drive the "System clock" for a very low power operation, but it can
        independently also be used for the watchdog timer (WDT) and other low
        frequency system timers like a real time clock.

config CPU_CLK_32K_XTAL
    bool "External 32.768 KHz crystal"
    depends on BOARD_HAS_XTAL32K

config CPU_CLK_32K_RCO
    bool "Internal 32 KHz oscillator"

endchoice

config BOARD_HAS_XTAL
    bool
    help
         Indicates that the board has an external high frequency crystal
         oscillator connected to the XTAL_IN / XTAL_OUT pins.
         This should only be set from board definition.

config BOARD_HAS_XTAL_16M
    bool
    imply BOARD_HAS_XTAL
    depends on !BOARD_HAS_XTAL_32M
    help
        Indicates that the external high frequency crystal oscillator is a
        16 MHz crystal. This should only be set from board definition.

config BOARD_HAS_XTAL_32M
    bool
    imply BOARD_HAS_XTAL
    help
        Indicates that the external high frequency crystal oscillator is a
        32 MHz crystal. This should only be set from board definition.

config CPU_CLK_OSC32M_DIV
    bool "Internal OSC32M clock input /2 divider"
    help
        Selecting this option will set the high-speed internal oscillator
        divider to /2, making it a 16 MHz clock source. See "System clock
        configuration selector" for selecting this source.

config CPU_CLK_XTAL_DIV
    bool "External XTAL 32 MHz clock input /2 divider"
    depends on BOARD_HAS_XTAL_32M
    help
        Selecting this option will set the high-speed external crystal
        oscillator divider to /2. This option is only available when the
        external oscillator is a 32 MHz one. See "System clock
        configuration selector" for selecting this source.

choice
    prompt "System clock configuration selector"
    default CPU_CLK_SYS_XTAL if BOARD_HAS_XTAL
    default CPU_CLK_SYS_OSC32M
    help
        The System clock is used to derive the AHB clock, which drives the ARM
        core and most peripherals.

config CPU_CLK_SYS_XTAL
    bool "External 16/32 MHz crystal source (with optional divider)"
    depends on BOARD_HAS_XTAL

config CPU_CLK_SYS_OSC32M
    bool "Internal 32 MHz oscillator source (with optional divider)"

config CPU_CLK_SYS_32K
    bool "Low frequency clock source (32 or 32.768 KHz)"

endchoice

config CPU_CLK_AHB_DIV
    int "AHB clock divider"
    default 1
    range 1 8192
    help
        The AHB clock is derived from the System clock using this divider value,
        between 1 and 8192, and serves as a clock source for ARM core, FSP, SCT,
        Quad-SPI, Flexcomm (UART, SPI, I2C), GPIO, BLE_AHB and DMA.
        Note: When BLE is enabled, the AHB clock must be at least the BLE clock
        (either 8 or 16 MHz) limiting the range of allowed values for this
        divider so that the AHB clock is 8, 16 or 32 MHz.

config CPU_CLK_APB_DIV
    int "APB clock divider"
    default 1
    range 1 16
    help
        The APB clock is derived from the AHB clock using this divide value,
        between 1 and 16, and serves as the clock source for several
        peripherals, such as the RTC, ADC, DAC, Capacitive Sense (CS) and
        optionally the WDT.

# TODO: Add USB PLL and BLE clock selectors.

endmenu