Add uart driver

src/Uart.cc

@@ -0,0 +1,89 @@
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <termios.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+
+#include <cstdlib>
+
+#include "Uart.h"
+
+Uart::Uart(const char* name)
+{
+    assert(name != nullptr);
+    serial_device = open(name, O_RDWR);
+    if (serial_device < 0)
+    {
+        printf("unable to open serial port\r\n");
+        exit(1);
+    }
+
+    // Create new termios struct, we call it 'tty' for convention
+    // No need for "= {0}" at the end as we'll immediately write the existing
+    // config to this struct
+    struct termios tty;
+
+    // Read in existing settings, and handle any error
+    // NOTE: This is important! POSIX states that the struct passed to tcsetattr()
+    // must have been initialized with a call to tcgetattr() overwise behaviour
+    // is undefined
+    if (tcgetattr(serial_device, &tty) != 0)
+    {
+        printf("Error %i from tcgetattr: %s\n", errno, strerror(errno));
+        close(serial_device);
+        exit(2);
+    }
+
+    tty.c_cflag |= PARENB; // Clear parity bit, disabling parity (most common)
+    tty.c_cflag &= ~PARODD;
+    tty.c_cflag &= ~CSTOPB; // Clear stop field, only one stop bit used in communication (most common)
+
+    tty.c_cflag &= ~CSIZE; // First clear all the size bits
+    tty.c_cflag |= CS8;    // 8 bits per byte (most common)
+
+    tty.c_cflag &= ~CRTSCTS;       // Disable RTS/CTS hardware flow control (most common)
+    tty.c_cflag |= CREAD | CLOCAL; // Turn on READ & ignore ctrl lines (CLOCAL = 1)
+
+    tty.c_lflag &= ~ICANON;
+    tty.c_lflag &= ~ECHO;   // Disable echo
+    tty.c_lflag &= ~ECHOE;  // Disable erasure
+    tty.c_lflag &= ~ECHONL; // Disable new-line echo
+    tty.c_lflag &= ~ISIG;   // Disable interpretation of INTR, QUIT and SUSP
+
+    tty.c_iflag &= ~(IXON | IXOFF | IXANY);                                      // Turn off s/w flow ctrl
+    tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL); // Disable any special handling of received bytes
+
+    tty.c_oflag &= ~OPOST; // Prevent special interpretation of output bytes (e.g. newline chars)
+    tty.c_oflag &= ~ONLCR; // Prevent conversion of newline to carriage return/line feed
+
+    tty.c_cc[VTIME] = 10; // Wait for up to 1s (10 deciseconds), returning as soon as any data is received.
+    tty.c_cc[VMIN] = 0;
+
+    cfsetispeed(&tty, B115200);
+    cfsetospeed(&tty, B115200);
+
+    // Save tty settings, also checking for error
+    if (tcsetattr(serial_device, TCSANOW, &tty) != 0)
+    {
+        printf("Error %i from tcsetattr: %s\n", errno, strerror(errno));
+        close(serial_device);
+        exit(3);
+    }
+}
+
+Uart::~Uart()
+{
+    close(serial_device);
+}
+
+int Uart::transmit(const unsigned char *buffer, size_t len)
+{
+    return write(serial_device, buffer, len);
+}
+
+int Uart::receive(unsigned char *buffer, size_t len)
+{
+    return read(serial_device, buffer, len);
+}

src/Uart.h

@@ -0,0 +1,19 @@
+#ifndef UART_H
+#define UART_H
+
+#include <cstring>
+
+class Uart
+{
+public:
+    Uart(const char *name);
+    ~Uart();
+
+     int transmit(const unsigned char *buffer, size_t len);
+     int receive(unsigned char *buffer, size_t len);
+
+private:
+     int serial_device = 0;
+};
+
+#endif