neorv32/sw/example/demo_spi/main.c

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2024-02-24 08:25:27 +00:00
// #################################################################################################
// # << NEORV32 - SPI Bus Explorer Demo Program >> #
// # ********************************************************************************************* #
// # BSD 3-Clause License #
// # #
// # Copyright (c) 2024, 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 #
// # 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. #
// # ********************************************************************************************* #
// # 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;
// 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();
// setup UART at default baud rate, no interrupts
neorv32_uart0_setup(BAUD_RATE, 0);
// 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("ERROR! 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_disable();
spi_configured = 0; // SPI not configured yet
// Main menu
for (;;) {
neorv32_uart0_printf("SPI_EXPLORER:> ");
length = neorv32_uart0_scan(buffer, 15, 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"
" en - enable single chip-select line (set low)\n"
" dis - disable all chip-select lines (set high)\n"
" trans - SPI data 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, "en")) {
spi_cs(1);
}
else if (!strcmp(buffer, "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 (spi_configured == 0) {
neorv32_uart0_printf("SPI module not configured yet! Use 'setup' to configure SPI module.\n");
return;
}
if (type) {
neorv32_uart0_printf("Chip-select line to ENABLE (set low) [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;
}
}
neorv32_spi_cs_en(channel);
}
else {
neorv32_uart0_printf("Disabling chip select lines.\n");
neorv32_spi_cs_dis();
}
}
/**********************************************************************//**
* SPI data transfer
**************************************************************************/
void spi_trans(void) {
char terminal_buffer[4];
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 (2 hex chars): 0x");
neorv32_uart0_scan(terminal_buffer, 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);
neorv32_uart0_printf("\nTX data: 0x");
aux_print_hex_byte(tx_data);
neorv32_uart0_printf("\nRX data: 0x");
aux_print_hex_byte(rx_data);
neorv32_uart0_printf("\n");
}
/**********************************************************************//**
* Configure SPI module
**************************************************************************/
void spi_setup(void) {
const uint32_t PRSC_LUT[8] = {2, 4, 8, 64, 128, 1024, 2048, 4096};
char terminal_buffer[9];
uint8_t spi_prsc, clk_div, clk_phase, clk_pol;
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;
}
}
neorv32_uart0_printf("\nEnter clock divider (0..15, as one hex char): ");
neorv32_uart0_scan(terminal_buffer, 2, 1);
clk_div = (uint8_t)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));
uint32_t clock = NEORV32_SYSINFO->CLK / (2 * PRSC_LUT[spi_prsc] * (1 + 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\n", tmp);
neorv32_spi_setup(spi_prsc, clk_div, clk_phase, clk_pol, 0);
spi_configured = 1; // SPI is configured now
}
/**********************************************************************//**
* 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]);
}