cy4

Usage

Overview

This driver provides an interface to Cyclades Cyclom-4Y, Cyclom-8Y and Cyclom-16Y asynchronous multiport serial boards. These boards are based around Cirrus Logic CD1400 communication controllers.

The device minor numbers for this driver are encoded as follows:

    d c c u u u u u	- bits in the minor device number
    bits    meaning
    ----    -------
    uuuuu   physical serial line (i.e., unit) to use
		0-7 on a cyclom-8Y, 0-15 on a cyclom-16Y
    cc      card number
    d       dial-out flag

Diagnostics

cy0: port 0 ibuf overrun

Incoming characters have been discarded due to a buffer overflow.

cy0: port 0 fifo overrun

Incoming characters have been discarded due to a CD1400 channel overrun. This is caused by interrupts not being serviced sufficiently quickly to prevent the 12 byte receive FIFO on a serial channel from overflowing. Reducing the value of the RX_FIFO_THRESHOLD #define from 6 to something smaller may help slow machines avoid this problem.