Subversion Repositories neorv32

// #################################################################################################

// # << NEORV32 - Blinking LED Demo Program >>                                                     #

// # ********************************************************************************************* #

// # BSD 3-Clause License                                                                          #

// #                                                                                               #

// # Copyright (c) 2021, Stephan Nolting. All rights reserved.                                     #

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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 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_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

  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

  }

}