// #################################################################################################
// # << NEORV32 - Blinking LED Demo Program >>                                                     #
// # ********************************************************************************************* #
// # BSD 3-Clause License                                                                          #
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// # Copyright (c) 2021, Stephan Nolting. All rights reserved.                                     #
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// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #
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/**********************************************************************//**
 * @file blink_led/main.c
 * @author Stephan Nolting
 * @brief Simple blinking LED demo program using the lowest 8 bits of the GPIO.output port.
 **************************************************************************/

#include <neorv32.h>


/**********************************************************************//**
 * @name User configuration
 **************************************************************************/
/**@{*/
/** UART BAUD rate */
#define BAUD_RATE 19200
/** Use the custom ASM version for blinking the LEDs defined (= uncommented) */
//#define USE_ASM_VERSION
/**@}*/


/**********************************************************************//**
 * ASM function to blink LEDs
 **************************************************************************/
extern void blink_led_asm(uint32_t gpio_out_addr);

/**********************************************************************//**
 * C function to blink LEDs
 **************************************************************************/
void blink_led_c(void);


/**********************************************************************//**
 * Main function; shows an incrementing 8-bit counter on GPIO.output(7:0).
 *
 * @note This program requires the GPIO controller to be synthesized (the UART is optional).
 *
 * @return 0 if execution was successful
 **************************************************************************/
int main() {

  // init UART (primary UART = UART0; if no id number is specified the primary UART is used) at default baud rate, no parity bits, ho hw flow control
  neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);

  // check if GPIO unit is implemented at all
  if (neorv32_gpio_available() == 0) {
    neorv32_uart0_print("Error! No GPIO unit synthesized!\n");
    return 1; // nope, no GPIO unit synthesized
  }

  // capture all exceptions and give debug info via UART
  // this is not required, but keeps us safe
  neorv32_rte_setup();

  // say hello
  neorv32_uart0_print("Blinking LED demo program\n");


// use ASM version of LED blinking (file: blink_led_in_asm.S)
#ifdef USE_ASM_VERSION

  blink_led_asm((uint32_t)(&NEORV32_GPIO.OUTPUT_LO));

// use C version of LED blinking
#else

  blink_led_c();

#endif
  return 0;
}


/**********************************************************************//**
 * C-version of blinky LED counter
 **************************************************************************/
void blink_led_c(void) {

  //neorv32_gpio_port_set(0); // clear gpio output

  int cnt = 0;

  while (1) {
    neorv32_gpio_port_set(cnt++ & 0xFF); // increment counter and mask for lowest 8 bit
    //neorv32_cpu_delay_ms(1); // wait 1ms using busy wait
  }
}
