NAME
cz —
Cyclades-Z series multi-port serial
adapter device
SYNOPSIS
cz* at pci?
DESCRIPTION
The cz device driver supports the
Cyclades-Z series of multi-port serial adapters. The Cyclades-Z is an
intelligent serial controller comprising:
- PLX9060ES PCI bus interface
- Xilinx XC5204 FPGA
- IDT R3052 MIPS CPU
The MIPS CPU runs firmware provided by the device driver. Communication with the MIPS is performed by modifying data structures located in board local RAM or host RAM.
The Cyclades-Z comes in three basic flavors:
- Cyclades-8Zo rev. 1 — This is an older 8-port board with no FPGA. The serial ports are provided by an octopus cable.
- Cyclades-8Zo rev. 2 — This is the newer 8-port board. The serial ports are provided by an octopus cable.
- Cyclades-Ze — This is the expandable version of the Cyclades-Z. It uses an HD-50 SCSI cable to connect the board to a 1U rack mountable serial expansion box. Each box has 16 RJ45 serial ports, and up to 4 boxes may be chained together, for a total of 64 ports. Boxes 3 and 4 require their own external power supply, otherwise the firmware will refuse to start (as it cannot communicate with the UARTs in those boxes).
The Cyclades-Z has several features to improve performance under high serial I/O load:
- The board may operate in interrupt-driven mode or polled mode to reduce interrupt load.
- Each channel has a large input and output buffer.
- Each channel may be programmed to generate an interrupt based on reception of a specific character, e.g. a PPP End-Of-Frame character.
- The MIPS CPU on the board performs all flow-control handling.
FILES
- /dev/ttyZ??
- dial-in (normal) TTY device
- /dev/cuaZ??
- dial-out TTY device
SEE ALSO
HISTORY
The cz driver first appeared in
OpenBSD 3.0.
AUTHORS
The cz driver was written by
Jason R. Thorpe
<thorpej@zembu.com>
and Bill Studenmund
<wrstuden@zembu.com>
of Zembu Labs, Inc.
BUGS
The cz driver does not currently implement
communication via host RAM. While this may improve performance by reducing
the number of PCI memory space read/write cycles, it is not straightforward
to implement with the current
bus_dma(9) API.
Interrupt mode has not been tested.
There is no support for reading or writing the EEPROM connected to the PLX PCI bus controller.