1
0
mirror of https://github.com/RIOT-OS/RIOT.git synced 2024-12-29 04:50:03 +01:00
RIOT/cpu/qn908x/cpu.c
iosabi cde8ac6093 cpu/qn908x: Initial minimal support for NXP QN908x CPUs.
The NXP QN908x CPU family is a Cortex-M4F CPU with integrated USB,
Bluetooth Low Energy and in some variants NFC. This patch implements the
first steps for having support for this CPU.

While the QN908x can be considered the successor of similar chips from
NXP like the KW41Z when looking at the feature set, the internal
architecture, boot image format and CPU peripherals don't match those
in the Kinetis line. Therefore, this patch creates a new directory for
just the QN908x chip under cpu/qn908x.

The minimal set of peripherals are implemented in this patch to allow
the device to boot and enable a GPIO: the gpio and wdt peripheral
modules only.

The wdt driver is required to boot and disable the wdt. On reset, the
wdt is disabled by the chip, however the QN908x bootloader stored in
the internal ROM enables the wdt and sets a timer to reboot after 10
seconds, therefore it is needed to disable the wdt in RIOT OS soon
after booting. This patch sets it up such that when no periph_wdt module
is used the Watchdog is disabled, but if the periph_wdt is used it must
be configured (initialized) within the first 10 seconds.

Tests performed:
Defined a custom board for this CPU and compiled a simple application
that blinks some LEDs. Manually tested with periph_wdt and with
periph_wdt_cb as well.
2020-12-02 02:47:07 +00:00

126 lines
3.7 KiB
C

/*
* 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.
*/
/**
* @ingroup cpu_qn908x
* @{
*
* @file
* @brief QN908x CPU initialization
*
* @author iosabi <iosabi@protonmail.com>
* @}
*/
#include "cpu.h"
#include "periph/init.h"
#include "stdio_base.h"
#include "vendor/drivers/fsl_clock.h"
static void cpu_clock_init(void);
/**
* @brief Initialize the CPU
*/
void cpu_init(void)
{
/* initialize the Cortex-M core */
cortexm_init();
#ifndef MODULE_PERIPH_WDT
/* If the `periph_wdt` is *not* being used (because the user does not care
* about that feature) we need to disable the Watchdog and continue running
* without it. Otherwise the CPU will reboot after about 10 seconds.
*/
CLOCK_DisableClock(kCLOCK_Wdt);
#endif /* ndef MODULE_PERIPH_WDT */
/* TODO: It would be good to move the VTOR to SRAM to allow execution from
* RAM with the FLASH memory off to allow for ultra low power operation on
* sleep mode. This needs to be done after cortexm_init() since it sets the
* VTOR to _isr_vectors which is the address on FLASH.
*/
/* initialize the clocks */
cpu_clock_init();
/* initialize stdio prior to periph_init() to allow use of DEBUG() there */
stdio_init();
/* trigger static peripheral initialization */
periph_init();
}
/* Set up clock speed configuration. See cpu_conf.h for details about the
* different clock options. */
void cpu_clock_init(void)
{
/* Set up external clock frequency. */
#if CONFIG_BOARD_HAS_XTAL
#if CONFIG_BOARD_HAS_XTAL_32M
CLOCK_AttachClk(k32M_to_XTAL_CLK); /* Switch XTAL_CLK to 32M */
#elif CONFIG_BOARD_HAS_XTAL_16M
CLOCK_AttachClk(k16M_to_XTAL_CLK); /* Switch XTAL_CLK to 16M */
#else
#error "One of the CONFIG_BOARD_XTAL_* must be set."
#endif
#endif /* CONFIG_BOARD_HAS_XTAL */
/* Set up 32K clock source. */
#if CONFIG_CPU_CLK_32K_XTAL
CLOCK_AttachClk(kXTAL32K_to_32K_CLK); /* Switch 32K_CLK to XTAL32K */
#elif CONFIG_CPU_CLK_32K_RCO
CLOCK_AttachClk(kRCO32K_to_32K_CLK); /* Switch 32K_CLK to RCO32K */
#else
#error "One of the CONFIG_CPU_CLK_32K_* must be set."
#endif
/* Set up System clock source. */
#if CONFIG_CPU_CLK_SYS_XTAL
CLOCK_AttachClk(kXTAL_to_SYS_CLK); /* Switch SYS_CLK to XTAL */
#elif CONFIG_CPU_CLK_SYS_OSC32M
CLOCK_AttachClk(kOSC32M_to_SYS_CLK); /* Switch SYS_CLK to OSM32M */
#elif CONFIG_CPU_CLK_SYS_32K
CLOCK_AttachClk(k32K_to_SYS_CLK); /* Switch SYS_CLK to 32K source */
#else
#error "One of the CONFIG_CPU_CLK_SYS_* must be set."
#endif
/* Run the WDT from the APB always. */
CLOCK_AttachClk(kAPB_to_WDT_CLK);
/* Set up dividers */
/* Set OSC32M_DIV divider */
#if CONFIG_CPU_CLK_OSC32M_DIV != 0 && CONFIG_CPU_CLK_OSC32M_DIV != 1
#error "Invalid CONFIG_CPU_CLK_OSC32M_DIV value"
#endif
/* Note: The denominator is set to (CONFIG_CPU_CLK_OSC32M_DIV + 1), so /2
* when the macro is enabled. */
CLOCK_SetClkDiv(kCLOCK_DivOsc32mClk, CONFIG_CPU_CLK_OSC32M_DIV);
/* Set XTAL_DIV divider */
#if CONFIG_CPU_CLK_XTAL_DIV != 0 && CONFIG_CPU_CLK_XTAL_DIV != 1
#error "Invalid CONFIG_CPU_CLK_XTAL_DIV value"
#endif
CLOCK_SetClkDiv(kCLOCK_DivXtalClk, CONFIG_CPU_CLK_XTAL_DIV);
/* Set AHB_DIV divider. */
#if CONFIG_CPU_CLK_AHB_DIV < 1 || CONFIG_CPU_CLK_AHB_DIV > 8192
#error "Invalid CONFIG_CPU_CLK_AHB_DIV"
#endif
CLOCK_SetClkDiv(kCLOCK_DivAhbClk, CONFIG_CPU_CLK_AHB_DIV - 1u);
/* Set APB_DIV divider. */
#if CONFIG_CPU_CLK_APB_DIV < 1 || CONFIG_CPU_CLK_APB_DIV > 16
#error "Invalid CONFIG_CPU_CLK_APB_DIV"
#endif
CLOCK_SetClkDiv(kCLOCK_DivApbClk, CONFIG_CPU_CLK_APB_DIV - 1u);
}