The driver enables RTS/CTS auto-flow control by setting the MCR register’s AFE bit. This prevents software intervention, drastically reducing overruns at high baud rates (e.g., 921600 bps). The driver’s role is limited to initial configuration and status monitoring.
In bare-metal systems, the driver often runs in a polled mode or simple interrupt context. With an RTOS like FreeRTOS, you can implement a proper serial driver with task notifications:
This decouples the driver from protocol handling, improving modularity.
static void xr16c950_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) // Set baud rate, parity, stop bits // Enable auto flow control if CRTSCTS is set uart_update_timeout(port, termios->c_cflag, baud); // Program EFR, TCR, TLR // Also handle RS-485 mode via TIOCSRS485 ioctlstatic void xr16c950_start_tx(struct uart_port *port) // Enable THRE interrupt unsigned char ier = serial_in(port, UART_IER); serial_out(port, UART_IER, ier
static void xr16c950_stop_tx(struct uart_port *port) // Disable THRE interrupt unsigned char ier = serial_in(port, UART_IER); serial_out(port, UART_IER, ier & ~UART_IER_THRI);
static irqreturn_t xr16c950_interrupt(int irq, void *dev_id) struct uart_port *port = dev_id; unsigned int iir = serial_in(port, UART_IIR); if (iir & UART_IIR_NO_INT) return IRQ_NONE;
// Handle Rx, Tx, line status based on IIR priority // Use FCR to manage FIFOs return IRQ_HANDLED;
cat /proc/tty/driver/serial
Check if the tx/rx FIFO size reports 128. If it shows 16, the generic 8250 driver is active.
In Linux, the 16C95x is typically supported via the 8250_pci or specific 16c95x serial drivers. The kernel abstracts the hardware via the TTY layer.
The driver enables RTS/CTS auto-flow control by setting the MCR register’s AFE bit. This prevents software intervention, drastically reducing overruns at high baud rates (e.g., 921600 bps). The driver’s role is limited to initial configuration and status monitoring.
In bare-metal systems, the driver often runs in a polled mode or simple interrupt context. With an RTOS like FreeRTOS, you can implement a proper serial driver with task notifications:
This decouples the driver from protocol handling, improving modularity. 16c95x serial port driver
static void xr16c950_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) // Set baud rate, parity, stop bits // Enable auto flow control if CRTSCTS is set uart_update_timeout(port, termios->c_cflag, baud); // Program EFR, TCR, TLR // Also handle RS-485 mode via TIOCSRS485 ioctlstatic void xr16c950_start_tx(struct uart_port *port) // Enable THRE interrupt unsigned char ier = serial_in(port, UART_IER); serial_out(port, UART_IER, ier
static void xr16c950_stop_tx(struct uart_port *port) // Disable THRE interrupt unsigned char ier = serial_in(port, UART_IER); serial_out(port, UART_IER, ier & ~UART_IER_THRI); The driver enables RTS/CTS auto-flow control by setting
static irqreturn_t xr16c950_interrupt(int irq, void *dev_id) struct uart_port *port = dev_id; unsigned int iir = serial_in(port, UART_IIR); if (iir & UART_IIR_NO_INT) return IRQ_NONE;
// Handle Rx, Tx, line status based on IIR priority // Use FCR to manage FIFOs return IRQ_HANDLED;
cat /proc/tty/driver/serial
Check if the tx/rx FIFO size reports 128. If it shows 16, the generic 8250 driver is active. This decouples the driver from protocol handling, improving
In Linux, the 16C95x is typically supported via the 8250_pci or specific 16c95x serial drivers. The kernel abstracts the hardware via the TTY layer.