Subversion Repositories neorv32

// #################################################################################################
// # << NEORV32 - Blinking LED Demo Program >>                                                     #
// # ********************************************************************************************* #
// # BSD 3-Clause License                                                                          #
// #                                                                                               #
// # Copyright (c) 2021, Stephan Nolting. 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.                                                                                #
// #                                                                                               #
// # 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               #
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// # ********************************************************************************************* #
// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #
// #################################################################################################
 
 
/**********************************************************************//**
 * @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_uart_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);
 
  // check if GPIO unit is implemented at all
  if (neorv32_gpio_available() == 0) {
    neorv32_uart_print("Error! No GPIO unit synthesized!\n");
    return 0; // 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();
 
  // check available hardware extensions and compare with compiler flags
  neorv32_rte_check_isa(0); // silent = 0 -> show message if isa mismatch
 
  // say hello
  neorv32_uart_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)(&GPIO_OUTPUT));
 
// 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 put
 
  int cnt = 0;
 
  while (1) {
    neorv32_gpio_port_set(cnt++ & 0xFF); // increment counter and mask for lowest 8 bit
    neorv32_cpu_delay_ms(200); // wait 200ms using busy wait
  }
}