//*****************************************************************************
//
//! @file binary_counter.c
//!
//! @brief Example that displays the timer count on the LEDs.
//!
//! This example increments a variable on every timer interrupt. The global
//! variable is used to set the state of the LEDs. The example sleeps otherwise.
//!
//! SWO is configured in 1M baud, 8-n-1 mode.
//
//*****************************************************************************

//*****************************************************************************
//
// Copyright (c) 2019, Ambiq Micro
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// 
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 
// 3. Neither the name of the copyright holder nor the names of its
// contributors may be used to endorse or promote products derived from this
// software without specific prior written permission.
// 
// Third party software included in this distribution is subject to the
// additional license terms as defined in the /docs/licenses directory.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// This is part of revision v2.2.0-7-g63f7c2ba1 of the AmbiqSuite Development Package.
//
//*****************************************************************************

#include "am_mcu_apollo.h"
#include "am_bsp.h"
#include "am_util.h"

volatile uint32_t g_ui32TimerCount = 0;

//*****************************************************************************
//
// Timer configuration.
//
//*****************************************************************************
am_hal_ctimer_config_t g_sTimer0 =
{
    // Don't link timers.
    0,

    // Set up Timer0A.
    (AM_HAL_CTIMER_FN_REPEAT |
     AM_HAL_CTIMER_INT_ENABLE    |
     AM_HAL_CTIMER_LFRC_32HZ),

    // No configuration for Timer0B.
    0,
};

//*****************************************************************************
//
// Function to initialize Timer A0 to interrupt every 1/4 second.
//
//*****************************************************************************
void
timerA0_init(void)
{
    uint32_t ui32Period;

    //
    // Enable the LFRC.
    //
    am_hal_clkgen_osc_start(AM_HAL_CLKGEN_OSC_LFRC);

    //
    // Set up timer A0.
    //
    am_hal_ctimer_clear(0, AM_HAL_CTIMER_TIMERA);
    am_hal_ctimer_config(0, &g_sTimer0);

    //
    // Set up timerA0 to 32Hz from LFRC divided to 1 second period.
    //
    ui32Period = 8;
    am_hal_ctimer_period_set(0, AM_HAL_CTIMER_TIMERA, ui32Period,
                             (ui32Period >> 1));

    //
    // Clear the timer Interrupt
    //
    am_hal_ctimer_int_clear(AM_HAL_CTIMER_INT_TIMERA0);
}

//*****************************************************************************
//
// Timer Interrupt Service Routine (ISR)
//
//*****************************************************************************
void
am_ctimer_isr(void)
{
    //
    // Increment count and set limit based on the number of LEDs available.
    //
    if (++g_ui32TimerCount >= (1 << AM_BSP_NUM_LEDS))
    {
        //
        // Reset the global.
        //
        g_ui32TimerCount = 0;
    }
    //
    // Clear TimerA0 Interrupt (write to clear).
    //
    am_hal_ctimer_int_clear(AM_HAL_CTIMER_INT_TIMERA0);

}

//*****************************************************************************
//
// Main function.
//
//*****************************************************************************
int
main(void)
{
    //
    // Set the clock frequency.
    //
    am_hal_clkgen_sysclk_select(AM_HAL_CLKGEN_SYSCLK_MAX);

    //
    // Set the default cache configuration
    //
    am_hal_cachectrl_enable(&am_hal_cachectrl_defaults);

    //
    // Configure the board for low power operation.
    //
    am_bsp_low_power_init();

    //
    // Initialize the printf interface for ITM/SWO output.
    //
    am_util_stdio_printf_init((am_util_stdio_print_char_t) am_bsp_itm_string_print);

    //
    // Initialize the SWO GPIO pin
    //
    am_bsp_pin_enable(ITM_SWO);
    am_devices_led_array_init(am_bsp_psLEDs, AM_BSP_NUM_LEDS);

    //
    // Enable the ITM.
    //
    am_hal_itm_enable();

    //
    // Enable debug printf messages using ITM on SWO pin
    //
    am_bsp_debug_printf_enable();

    //
    // Clear the terminal and print the banner.
    //
    am_util_stdio_terminal_clear();
    am_util_stdio_printf("Binary Counter Example\n");

    //
    // TimerA0 init.
    //
    timerA0_init();

    //
    // Enable the timer Interrupt.
    //
    am_hal_ctimer_int_enable(AM_HAL_CTIMER_INT_TIMERA0);

    //
    // Enable the timer interrupt in the NVIC.
    //
    am_hal_interrupt_enable(AM_HAL_INTERRUPT_CTIMER);
    am_hal_interrupt_master_enable();

    //
    // Start timer A0
    //
    am_hal_ctimer_start(0, AM_HAL_CTIMER_TIMERA);

    //
    // We are done printing. Disable debug printf messages on ITM.
    //
    am_bsp_debug_printf_disable();

    //
    // Loop forever.
    //
    while (1)
    {
        //
        // Go to Deep Sleep.
        //
        am_hal_sysctrl_sleep(AM_HAL_SYSCTRL_SLEEP_DEEP);

        //
        // Set the LEDs.
        //
        am_devices_led_array_out(am_bsp_psLEDs, AM_BSP_NUM_LEDS,
                         g_ui32TimerCount);
    }
}
