348 lines
13 KiB
C
348 lines
13 KiB
C
// #################################################################################################
|
|
// # << NEORV32 - TWI 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. #
|
|
// # #
|
|
// # 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_twi/main.c
|
|
* @author Stephan Nolting
|
|
* @brief TWI bus explorer.
|
|
**************************************************************************/
|
|
|
|
#include <neorv32.h>
|
|
#include <string.h>
|
|
|
|
|
|
/**********************************************************************//**
|
|
* @name User configuration
|
|
**************************************************************************/
|
|
/**@{*/
|
|
/** UART BAUD rate */
|
|
#define BAUD_RATE 19200
|
|
/**@}*/
|
|
|
|
|
|
// Prototypes
|
|
void scan_twi(void);
|
|
void set_clock(void);
|
|
void send_twi(void);
|
|
void check_claimed(void);
|
|
void toggle_mack(void);
|
|
uint32_t hexstr_to_uint(char *buffer, uint8_t length);
|
|
void print_hex_byte(uint8_t data);
|
|
|
|
// Global variables
|
|
int bus_claimed;
|
|
|
|
|
|
/**********************************************************************//**
|
|
* This program provides an interactive console to communicate with TWI devices.
|
|
*
|
|
* @note This program requires the UART and the PWM to be synthesized.
|
|
*
|
|
* @return 0 if execution was successful
|
|
**************************************************************************/
|
|
int main() {
|
|
|
|
char buffer[8];
|
|
int length = 0;
|
|
bus_claimed = 0;
|
|
|
|
// check if UART unit is implemented at all
|
|
if (neorv32_uart0_available() == 0) {
|
|
return 1;
|
|
}
|
|
|
|
|
|
// capture all exceptions and give debug info via UART
|
|
// this is not required, but keeps us safe
|
|
neorv32_rte_setup();
|
|
|
|
|
|
// init UART at default baud rate, no parity bits, ho hw flow control
|
|
neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);
|
|
|
|
// check available hardware extensions and compare with compiler flags
|
|
neorv32_rte_check_isa(0); // silent = 0 -> show message if isa mismatch
|
|
|
|
// intro
|
|
neorv32_uart0_printf("\n--- TWI Bus Explorer ---\n\n");
|
|
|
|
|
|
// check if TWI unit is implemented at all
|
|
if (neorv32_twi_available() == 0) {
|
|
neorv32_uart0_printf("No TWI unit implemented.");
|
|
return 1;
|
|
}
|
|
|
|
|
|
// info
|
|
neorv32_uart0_printf("This program allows to create TWI transfers by hand.\n"
|
|
"Type 'help' to see the help menu.\n\n");
|
|
|
|
// configure TWI, second slowest clock, no clock stretching
|
|
neorv32_twi_setup(CLK_PRSC_2048, 15, 0);
|
|
|
|
// no active bus session yet
|
|
bus_claimed = 0;
|
|
|
|
// Main menu
|
|
for (;;) {
|
|
neorv32_uart0_printf("TWI_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"
|
|
" scan - scan bus for devices\n"
|
|
" start - generate START condition\n"
|
|
" stop - generate STOP condition\n"
|
|
" send - write & read single byte to/from bus\n"
|
|
" clock - configure bus clock (will reset TWI module!)\n"
|
|
" stat - check if the TWI bus is currently claimed by any controller\n"
|
|
" mack - enable/disable MASTER-ACK (ACK send by controller)\n\n"
|
|
"Start a new transmission by generating a START condition. Next, transfer the 7-bit device address\n"
|
|
"and the R/W flag. After that, transfer your data to be written or send a 0xFF if you want to read\n"
|
|
"data from the bus. Finish the transmission by generating a STOP condition.\n\n");
|
|
}
|
|
else if (!strcmp(buffer, "start")) {
|
|
neorv32_twi_generate_start(); // generate START condition
|
|
bus_claimed = 1;
|
|
}
|
|
else if (!strcmp(buffer, "stop")) {
|
|
if (bus_claimed == 0) {
|
|
neorv32_uart0_printf("No active I2C transmission.\n");
|
|
continue;
|
|
}
|
|
neorv32_twi_generate_stop(); // generate STOP condition
|
|
bus_claimed = 0;
|
|
}
|
|
else if (!strcmp(buffer, "scan")) {
|
|
scan_twi();
|
|
}
|
|
else if (!strcmp(buffer, "clock")) {
|
|
set_clock();
|
|
}
|
|
else if (!strcmp(buffer, "send")) {
|
|
if (bus_claimed == 0) {
|
|
neorv32_uart0_printf("No active I2C transmission. Generate a START condition first.\n");
|
|
continue;
|
|
}
|
|
else {
|
|
send_twi();
|
|
}
|
|
}
|
|
else if (!strcmp(buffer, "stat")) {
|
|
check_claimed();
|
|
}
|
|
else if (!strcmp(buffer, "mack")) {
|
|
toggle_mack();
|
|
}
|
|
else {
|
|
neorv32_uart0_printf("Invalid command. Type 'help' to see all commands.\n");
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/**********************************************************************//**
|
|
* TWI clock speed menu
|
|
**************************************************************************/
|
|
void set_clock(void) {
|
|
|
|
const uint32_t PRSC_LUT[8] = {2, 4, 8, 64, 128, 1024, 2048, 4096};
|
|
char terminal_buffer[2];
|
|
|
|
neorv32_uart0_printf("Select new clock prescaler (0..7; one hex char): ");
|
|
neorv32_uart0_scan(terminal_buffer, 2, 1); // 1 hex char plus '\0'
|
|
int prsc = (int)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));
|
|
|
|
if ((prsc < 0) || (prsc > 7)) { // invalid?
|
|
neorv32_uart0_printf("\nInvalid selection!\n");
|
|
return;
|
|
}
|
|
|
|
neorv32_uart0_printf("\nSelect new clock divider (0..15; one hex char): ");
|
|
neorv32_uart0_scan(terminal_buffer, 2, 1); // 1 hex char plus '\0'
|
|
int cdiv = (int)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));
|
|
|
|
neorv32_uart0_printf("\nEnable clock stretching (0=no, 1=yes)? ");
|
|
neorv32_uart0_scan(terminal_buffer, 2, 1); // 1 hex char plus '\0'
|
|
int csen = (int)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));
|
|
|
|
// set new configuration
|
|
neorv32_twi_setup(prsc, cdiv, csen);
|
|
bus_claimed = 0;
|
|
|
|
// print new clock frequency
|
|
uint32_t clock = NEORV32_SYSINFO.CLK / (4 * PRSC_LUT[prsc] * (1 + cdiv));
|
|
neorv32_uart0_printf("\nNew I2C clock: %u Hz\n", clock);
|
|
}
|
|
|
|
|
|
/**********************************************************************//**
|
|
* Scan 7-bit TWI address space and print results
|
|
**************************************************************************/
|
|
void scan_twi(void) {
|
|
|
|
neorv32_uart0_printf("Scanning TWI bus...\n");
|
|
uint8_t i, num_devices = 0;
|
|
for (i=0; i<128; i++) {
|
|
uint8_t twi_ack = neorv32_twi_start_trans((uint8_t)(2*i+1));
|
|
neorv32_twi_generate_stop();
|
|
|
|
if (twi_ack == 0) {
|
|
neorv32_uart0_printf(" + Found device at write-address 0x");
|
|
print_hex_byte(2*i);
|
|
neorv32_uart0_printf("\n");
|
|
num_devices++;
|
|
}
|
|
}
|
|
|
|
if (!num_devices) {
|
|
neorv32_uart0_printf("No devices found.\n");
|
|
}
|
|
}
|
|
|
|
|
|
/**********************************************************************//**
|
|
* Check if the TWI is currently claimed.
|
|
**************************************************************************/
|
|
void check_claimed(void) {
|
|
|
|
if (NEORV32_TWI.CTRL & (1 << TWI_CTRL_CLAIMED)) {
|
|
if (bus_claimed == 0) {
|
|
neorv32_uart0_printf("Bus claimed by another controller.\n");
|
|
}
|
|
else {
|
|
neorv32_uart0_printf("Bus claimed by NEORV32 TWI.\n");
|
|
}
|
|
}
|
|
else {
|
|
neorv32_uart0_printf("Bus is idle.\n");
|
|
}
|
|
}
|
|
|
|
|
|
/**********************************************************************//**
|
|
* Toggle MACK (ACK generated by controller/host)
|
|
**************************************************************************/
|
|
void toggle_mack(void) {
|
|
|
|
// toggle MACK flag
|
|
NEORV32_TWI.CTRL ^= 1 << TWI_CTRL_MACK;
|
|
|
|
if (NEORV32_TWI.CTRL & (1 << TWI_CTRL_MACK)) {
|
|
neorv32_uart0_printf("MACK enabled.\n");
|
|
}
|
|
else {
|
|
neorv32_uart0_printf("MACK disabled.\n");
|
|
}
|
|
}
|
|
|
|
|
|
/**********************************************************************//**
|
|
* Read/write menu to transfer 1 byte from/to bus
|
|
**************************************************************************/
|
|
void send_twi(void) {
|
|
|
|
char terminal_buffer[4];
|
|
|
|
// enter data
|
|
neorv32_uart0_printf("Enter TX data (2 hex chars): ");
|
|
neorv32_uart0_scan(terminal_buffer, 3, 1); // 2 hex chars for address plus '\0'
|
|
uint8_t tmp = (uint8_t)hexstr_to_uint(terminal_buffer, strlen(terminal_buffer));
|
|
uint8_t res = neorv32_twi_trans(tmp);
|
|
neorv32_uart0_printf("\n RX data: 0x");
|
|
print_hex_byte((uint8_t)neorv32_twi_get_data());
|
|
neorv32_uart0_printf("\n Response: ");
|
|
if (res == 0)
|
|
neorv32_uart0_printf("ACK\n");
|
|
else
|
|
neorv32_uart0_printf("NACK\n");
|
|
|
|
}
|
|
|
|
|
|
/**********************************************************************//**
|
|
* 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 byte as hex chars via UART0.
|
|
*
|
|
* @param data 8-bit data to be printed as two hex chars.
|
|
**************************************************************************/
|
|
void print_hex_byte(uint8_t data) {
|
|
|
|
static const char symbols[] = "0123456789abcdef";
|
|
|
|
neorv32_uart0_putc(symbols[(data >> 4) & 15]);
|
|
neorv32_uart0_putc(symbols[(data >> 0) & 15]);
|
|
}
|
|
|