Subversion Repositories neorv32

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

// # << NEORV32 - SPI Bus Explorer 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.                                                   #

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// #    conditions and the following disclaimer in the documentation and/or other materials        #

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// # 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.                                                                                #

// #                                                                                               #

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

// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #

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

/**********************************************************************//**

 * @file demo_spi/main.c

 * @author Stephan Nolting

 * @brief SPI bus explorer (execute SPI transactions by hand).

 **************************************************************************/

#include <neorv32.h>

#include <string.h>

/**********************************************************************//**

 * @name User configuration

 **************************************************************************/

/**@{*/

/** UART BAUD rate */

#define BAUD_RATE 19200

/**@}*/

// Global variables

uint32_t spi_configured;

uint32_t spi_size; // data quantity in bytes

// Prototypes

void spi_cs(uint32_t type);

void spi_trans(void);

void spi_setup(void);

uint32_t hexstr_to_uint(char *buffer, uint8_t length);

void aux_print_hex_byte(uint8_t byte);

/**********************************************************************//**

 * This program provides an interactive console to communicate with SPI devices.

 *

 * @note This program requires the UART and the SPI to be synthesized.

 *

 * @return Irrelevant.

 **************************************************************************/

int main() {

  char buffer[8];

  int length = 0;

  // capture all exceptions and give debug info via UART

  // this is not required, but keeps us safe

  neorv32_rte_setup();

  // init UART0 at default baud rate, no parity bits, ho hw flow control

  neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);

  // check if UART0 unit is implemented at all

  if (neorv32_uart0_available() == 0) {

    return 1;

  }

  // intro

  neorv32_uart0_printf("\n<<< SPI Bus Explorer >>>\n\n");

  // check if SPI unit is implemented at all

  if (neorv32_spi_available() == 0) {

    neorv32_uart0_printf("No SPI unit implemented.");

    return 1;

  }

  // info

  neorv32_uart0_printf("This program allows to create SPI transfers by hand.\n"

                      "Type 'help' to see the help menu.\n\n");

  // disable and reset SPI module

  NEORV32_SPI.CTRL = 0;

  spi_configured = 0; // SPI not configured yet

  spi_size = 0;

  // Main menu

  for (;;) {

    neorv32_uart0_printf("SPI_EXPLORER:> ");

    length = neorv32_uart0_scan(buffer, 8, 1);

    neorv32_uart0_printf("\n");

    if (!length) // nothing to be done

     continue;

    // decode input and execute command

    if (!strcmp(buffer, "help")) {

      neorv32_uart0_printf("Available commands:\n"

                          " help   - show this text\n"

                          " setup  - configure SPI module\n"

                          " cs-en  - enable CS line (set low)\n"

                          " cs-dis - disable CS line (set high)\n"

                          " trans  - execute a transmission (write & read to/from SPI)\n"

                          "\n"

                          "Configure the SPI module using 'setup'. Enable a certain module using 'cs-en',\n"

                          "then transfer data using 'trans' and disable the module again using 'cs-dis'.\n\n");

    }

    else if (!strcmp(buffer, "setup")) {

      spi_setup();

    }

    else if (!strcmp(buffer, "cs-en")) {

      spi_cs(1);

    }

    else if (!strcmp(buffer, "cs-dis")) {

      spi_cs(0);

    }

    else if (!strcmp(buffer, "trans")) {

      spi_trans();

    }

    else {

      neorv32_uart0_printf("Invalid command. Type 'help' to see all commands.\n");

    }

  }

  return 0;

}

/**********************************************************************//**

 * Enable or disable chip-select line

 *

 * @param[in] type 0=disable, 1=enable

 **************************************************************************/

void spi_cs(uint32_t type) {

  char terminal_buffer[2];

  uint8_t channel;

  if (type) {

    neorv32_uart0_printf("Select chip-select line to enable (set low) [0..7]: ");

  }

  else {

    neorv32_uart0_printf("Select chip-select line to disable (set high) [0..7]: ");

  }

  while (1) {

    neorv32_uart0_scan(terminal_buffer, 2, 1); // 1 hex char plus '\0'

    channel = (uint8_t)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));

    if (channel > 7) {

      neorv32_uart0_printf("\nInvalid channel selection!\n");

      return;

    }

    else {

      neorv32_uart0_printf("\n");

      break;

    }

  }

  if (type) {

    neorv32_spi_cs_en(channel);

  }

  else {

    neorv32_spi_cs_dis(channel);

  }

}

/**********************************************************************//**

 * SPI data transfer

 **************************************************************************/

void spi_trans(void) {

  char terminal_buffer[9];

  if (spi_configured == 0) {

    neorv32_uart0_printf("SPI module not configured yet! Use 'setup' to configure SPI module.\n");

    return;

  }

  neorv32_uart0_printf("Enter TX data (%u hex chars): 0x", spi_size);

  neorv32_uart0_scan(terminal_buffer, spi_size*2+1, 1);

  uint32_t tx_data = (uint32_t)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));

  uint32_t rx_data = neorv32_spi_trans(tx_data);

  if (spi_size == 1) {

    neorv32_uart0_printf("\nTX data: 0x");

    aux_print_hex_byte((uint8_t)(tx_data));

    neorv32_uart0_printf("\nRX data: 0x");

    aux_print_hex_byte((uint8_t)(rx_data));

    neorv32_uart0_printf("\n");

  }

  else if (spi_size == 2) {

    neorv32_uart0_printf("\nTX data: 0x");

    aux_print_hex_byte((uint8_t)(tx_data >> 8));

    aux_print_hex_byte((uint8_t)(tx_data));

    neorv32_uart0_printf("\nRX data: 0x");

    aux_print_hex_byte((uint8_t)(rx_data >> 8));

    aux_print_hex_byte((uint8_t)(rx_data));

    neorv32_uart0_printf("\n");

  }

  else if (spi_size == 3) {

    neorv32_uart0_printf("\nTX data: 0x");

    aux_print_hex_byte((uint8_t)(tx_data >> 16));

    aux_print_hex_byte((uint8_t)(tx_data >> 8));

    aux_print_hex_byte((uint8_t)(tx_data));

    neorv32_uart0_printf("\nRX data: 0x");

    aux_print_hex_byte((uint8_t)(rx_data >> 16));

    aux_print_hex_byte((uint8_t)(rx_data >> 8));

    aux_print_hex_byte((uint8_t)(rx_data));

    neorv32_uart0_printf("\n");

  }

  else {

    neorv32_uart0_printf("\nTX data: 0x%x\n", tx_data);

    neorv32_uart0_printf("RX data: 0x%x\n", rx_data);

  }

}

/**********************************************************************//**

 * Configure SPI module

 **************************************************************************/

void spi_setup(void) {

  char terminal_buffer[9];

  uint8_t spi_prsc, clk_phase, clk_pol, data_size;

  uint32_t tmp;

  // ---- SPI clock ----

  while (1) {

  neorv32_uart0_printf("Select SPI clock prescaler (0..7): ");

  neorv32_uart0_scan(terminal_buffer, 2, 1);

  tmp = (uint32_t)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));

    if (tmp > 8) {

      neorv32_uart0_printf("\nInvalid selection!\n");

    }

    else {

      spi_prsc = (uint8_t)tmp;

      break;

    }

  }

  uint32_t div = 0;

  switch (spi_prsc) {

    case 0: div = 2 * 2; break;

    case 1: div = 2 * 4; break;

    case 2: div = 2 * 8; break;

    case 3: div = 2 * 64; break;

    case 4: div = 2 * 128; break;

    case 5: div = 2 * 1024; break;

    case 6: div = 2 * 2048; break;

    case 7: div = 2 * 4096; break;

    default: div = 0; break;

  }

  uint32_t clock = NEORV32_SYSINFO.CLK / div;

  neorv32_uart0_printf("\n+ New SPI clock speed = %u Hz\n", clock);

  // ---- SPI clock mode ----

  while (1) {

  neorv32_uart0_printf("Select SPI clock mode (0..3): ");

  neorv32_uart0_scan(terminal_buffer, 2, 1);

  tmp = (uint32_t)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));

    if (tmp > 4) {

      neorv32_uart0_printf("\nInvalid selection!\n");

    }

    else {

      clk_pol   = (uint8_t)((tmp >> 1) & 1);

      clk_phase = (uint8_t)(tmp & 1);

      break;

    }

  }

  neorv32_uart0_printf("\n+ New SPI clock mode = %u\n", tmp);

  // ---- SPI transfer data quantity ----

  while (1) {

  neorv32_uart0_printf("Select SPI data transfer size in bytes (1,2,3,4): ");

  neorv32_uart0_scan(terminal_buffer, 2, 1);

  tmp = (uint32_t)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));

    if ( (tmp < 1) || (tmp > 4)) {

      neorv32_uart0_printf("\nInvalid selection!\n");

    }

    else {

      data_size = (uint8_t)(tmp - 1);

      break;

    }

  }

  neorv32_uart0_printf("\n+ New SPI data size = %u-byte(s)\n\n", tmp);

  neorv32_spi_setup(spi_prsc, clk_phase, clk_pol, data_size);

  spi_configured = 1; // SPI is configured now

  spi_size = tmp;

}

/**********************************************************************//**

 * Helper function to convert N hex chars string into uint32_T

 *

 * @param[in,out] buffer Pointer to array of chars to convert into number.

 * @param[in,out] length Length of the conversion string.

 * @return Converted number.

 **************************************************************************/

uint32_t hexstr_to_uint(char *buffer, uint8_t length) {

  uint32_t res = 0, d = 0;

  char c = 0;

  while (length--) {

    c = *buffer++;

    if ((c >= '0') && (c <= '9'))

      d = (uint32_t)(c - '0');

    else if ((c >= 'a') && (c <= 'f'))

      d = (uint32_t)((c - 'a') + 10);

    else if ((c >= 'A') && (c <= 'F'))

      d = (uint32_t)((c - 'A') + 10);

    else

      d = 0;

    res = res + (d << (length*4));

  }

  return res;

}

/**********************************************************************//**

 * Print HEX byte.

 *

 * @param[in] byte Byte to be printed as 2-cahr hex value.

 **************************************************************************/

void aux_print_hex_byte(uint8_t byte) {

  static const char symbols[] = "0123456789abcdef";

  neorv32_uart0_putc(symbols[(byte >> 4) & 0x0f]);

  neorv32_uart0_putc(symbols[(byte >> 0) & 0x0f]);

}