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User-space interface to ppbus parallel 'geek' port under FreeBSD
This extension uses C functions from FreeBSD's ppi to implement simple procedures for handling Parallel Port's input and output.[procedure] (ppi-in DEVICE REQUEST)
Gets the contents of the corresponding register on the given device[procedure] (ppi-out DEVICE REQUEST NUMBER)
Sets the contents of the corresponding register on the given device
- DEVICE is a string indicating a path to the device's file (eg. "/dev/ppi0")
- REQUEST is one of
with a meaning as described in man ppi.
There are predefined procedures to set and get various registers[procedure] ppi-data-in
Each ppi-***-in procedure is a procedure of no arguments. Each ppi-***-out procedure is a procedure of one argument being the number to send to register.
For example: <procedure>(ppi-data-out NUMBER)</procedure>
Sets the contents of the data register to given number There are 8 bits in the data register so range of numbers available to set is 0 - 255
Example : <example><expr>(ppi-data-out 5)</expr></example> sets D2 and D0 to logical 1
<example><expr>(ppi-status-in)</expr></example> -> 8 * S3 + 16 * S4 + 32 * S5 + 64 * S6 + 128 * ~S7 reads the contents of the status register.
Example : For S3 and S5 set to 1 and the rest to 0 (ppi-status-in) -> 40
The predefined procedures make usage of the device /dev/ppi0 as the parallel port. If you want them to use another device, you can change it, as the device's name to use is bound with ppi-device variable.
Example: To read control register on /dev/ppi1 device you can use either
(ppi-in "/dev/ppi1" PPIGCTRL)
(set! ppi-device "/dev/ppi1") (ppi-control-in)
In the latter case, consequent calls to ppi-***-in/out procedures will obviously refer to "/dev/ppi1" device.
For further reference on ppi see man ppi
There are many sites devoted to parallel port operations, for example:
- 1.1 Added freebsd platform specifier to meta file
- 1.0 Initial version<
Copyright (c) 2005 Michal Dybizbanski
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