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3 .\" Copyright (c) 1998 Iain Hibbert
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32 Magma Sp Serial/Parallel board device driver
34 .Cd "magma* at sbus? slot ? offset ?"
40 driver provides an interface to Magma LC2+1Sp, 2+1Sp, 4+1Sp, 8+2Sp,
41 4Sp, 8Sp, 12Sp, 16Sp, 1P and 2P boards.
42 These boards are based around the Cirrus Logic CD1400 serial/parallel
43 communications engine and the Cirrus Logic CD1190 parallel
44 communications engine.
46 The device minor numbers for this driver are encoded as follows:
49 +---+---+---+---+---+---+---+---+
50 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
51 +---+---+---+---+---+---+---+---+
53 | | | | +---+---+---+---\*[Gt] port number
55 | | | +-------------------\*[Gt] dial-out (on tty ports)
57 | | +-----------------------\*[Gt] unused
59 +---+---------------------------\*[Gt] card number
62 Up to four cards are supported in the system.
64 All tty ports have full automatic hardware (RTS/CTS) flow control available
65 and a 12 byte FIFO on the chip in each direction so errors should be minimal.
67 .Bl -tag -width /dev/bpp[0-3][0-1] -compact
68 .It Pa /dev/tty[0-3][0-a]
70 .It Pa /dev/bpp[0-3][0-1]
75 .It "mtty%d%x: ring buffer overflow"
76 Incoming characters have been discarded due to a buffer overflow.
77 This is caused by the process in control of the device not reading
78 characters fast enough.
80 If need be you can make the ring buffer bigger by changing the
82 #define to something bigger, but it should be a multiple
84 .It "mtty%d%x: fifo overflow"
85 Incoming characters have been discarded due to a CD1400 channel overrun.
86 This is caused by interrupts not being serviced sufficiently quickly
87 to prevent the 12 byte receive FIFO on a serial channel from overflowing.
89 Reducing the value of either the
90 .Dv MTTY_RX_FIFO_THRESHOLD
92 .Dv MTTY_RX_DTR_THRESHOLD
93 #define's to something smaller may help slow machines avoid this problem.
100 The driver was loosely based upon the
102 Cyclades Cyclom device driver written
103 by Andrew Herbert and Timo Rossi.
105 The driver was written by
108 CD1190 parallel support.
113 Dial-out (cua) devices are not yet supported.
121 Automatic XON/XOFF handshaking could be implemented fairly easily.
123 It would be good if the tty port waited for the FIFO to empty before allowing
124 a close, so that I could turn off the channel interrupts at that time.