zsc - Zilog 8530 (ZSCC) serial communications driver
zsc0 at obio?
zstty* at zsc? channel ?
The zsc driver provides support for Z8530- and Z85230-compatible EIA
RS-232C (CCITT V.28) Dual UART chips. The Z8530 has a 3
character
buffer, while the Z85230 has a 8 character buffer. However,
due to limitations
in the design of the Z85230, the driver is unable to
distinguish
it from the Z8530 and will not enable any enhanced features
of the device.
Input and output for each line may be set to any baud rate
in the range
from 50 to 115200 (though some machines will not support
more than 38400
reliably).
The zstty driver provides a terminal interface, supporting
all the standard
tty(4) ioctl calls.
/dev/ttya
/dev/ttyb
ioctl(2), intro(4), obio(4), tty(4)
Due to the small character buffer on the Zilog 8530 chip,
the driver has
very strict latency requirements for its interrupt service
routine. As a
result, data loss may occur when using high speeds, particularly on older
(68020 or 68030) Macintosh models and on busy systems.
OpenBSD 3.6 March 8, 2004
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