parallel.library Reference

Comprehensive function reference for parallel.library, synthesised from the AmigaOS NDK 3.2 Release 4 (Autodocs/AG/parallel).

This page documents 10 functions of parallel.library. Each function entry follows the canonical autodoc format. struct Name, union Name, enum Name are clickable links to the type definition in the types reference.

Function index

CMD_CLEAR()

Clear -- clear the parallel port buffer

Function

This command just RTS's (no buffer to clear)

IO REQUEST io_Message mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command CMD_CLEAR (05)

CMD_FLUSH()

Flush -- clear all queued I/O requests for the parallel port

Function

This command purges the read and write request queues for the parallel device. The currently active request is not purged.

IO REQUEST io_Message mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command CMD_FLUSH (08)

CMD_READ()

Read -- read input from parallel port

Function

This command causes a stream of characters to be read from the parallel I/O register. The number of characters is specified in io_Length. The EOF and EOL modes are supported, but be warned that using these modes can result in a buffer overflow if the proper EOL or EOF character is not received in time. These modes should be used only when the sender and receiver have been designed to cooperate. A safety guard can be implemented to EOF by setting io_Length to a maximum allowed value. That cannot be done with EOL since the EOL mode is identified by io_Length=-1.

The parallel.device has no internal buffer; if no read request has
been made, pending input (i.e. handshake request) is not
acknowledged.

IO REQUEST io_Message mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command CMD_READ (02) io_Flags If IOF_QUICK is set, driver will attempt Quick IO io_Length number of characters to receive. io_Data pointer where to put the data.

Results

io_Error -- if the Read succeded, then io_Error will be null. If the Read failed, then io_Error will contain an error code.

CMD_RESET()

Reset -- reinitializes the parallel device

Function

This command resets the parallel device to its freshly initialized condition. It aborts all I/O requests both queued and current and sets the devices's flags and parameters to their boot-up time default values. At boot-up time the PTermArray is random, and it will be so also here.

IO REQUEST io_Message mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command CMD_RESET (01)

Results

Error -- if the Reset succeded, then io_Error will be null. if the Reset failed, then the io_Error will be non-zero.

CMD_START()

Start -- restart paused I/O over the parallel port

Function

This command restarts the current I/O activity on the parallel port by reactivating the handshaking sequence.

IO REQUEST io_Message mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command CMD_START (07)

CMD_STOP()

Stop -- pause current activity on the parallel device

Function

This command halts the current I/O activity on the parallel device by discontinuing the handshaking sequence. The stop and start commands may not be nested.

IO REQUEST io_Message mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command CMD_STOP (06)

CMD_WRITE()

Write -- send output to parallel port

Function

This command causes a stream of characters to be written to the parallel output register. The number of characters is specified in io_Length, unless -1 is used, in which case output is sent until a zero byte occurs in the data. This is independent of, and may be used simultaneously with setting the EOFMODE in io_ParFlags and using the PTermArray to terminate the read or write.

IO REQUEST io_Message mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command CMD_WRITE (03) io_Flags If IOF_QUICK is set, driver will attempt Quick IO io_Length number of characters to transmit, or if set to -1 send until zero byte encountered io_Data pointer to block of data to transmit

Results

io_Error -- If the Write succeded, then io_Error will be null. If the Write failed, then io_Error will contain an error code.

OpenDevice()

Open -- a request to open the parallel port

Synopsis

error = OpenDevice("parallel.device", unit, ioExtPar, flags) D0 A0 D0 A1 D1

Function

This function allows the requestor software access to the parallel device. Unless the shared-access bit (bit 5 of io_ParFlags) is set, exclusive use is granted and no other access is allowed until the owner closes the device.

A FAST_MODE, can be specified (bit 3 of io_Parflags) to speed up
transfers to high-speed printers. Rather than waiting for the printer
to acknowledge a character using the *ACK interrupt, this mode will
send out data as long as the BUSY signal is low. The printer must be
able to raise the BUSY signal within 3 micro-seconds on A2630s,
otherwise data will be lost. Should be used only in an exclusive-
access Open().

A SLOWMODE mode can be specified (bit 4 of io_ParFlags) when very
slow printers are used. If the printer acknowledges data at less
than 5000 bytes per second, then this mode will actually save CPU
time, although it consumes much more with high-speed printers.

The PTermArray of the ioExtPar is initialized only if the EOFMODE
bit (bit 1 of io_ParFlags) is set. The PTermArray can be further
modified using the PDCMD_SETPARAMS command.

Inputs

"parallel.device" - a pointer to literal string "parallel.device" unit - Must be zero for future compatibility ioExtPar - pointer to an IO Request block of structure IOExtPar to be initialized by the Open() function. The io_ParFlags field must be set as desired. flags - Must be zero for future compatibility

Results

d0 -- same as io_Error io_Error -- if the Open succeded, then io_Error will be null. If the Open failed, then io_Error will be non-zero.

See also

CloseDevice()

PDCMD_QUERY()

Query -- query parallel port/line status

Function

This command return the status of the parallel port lines and registers.

IO REQUEST io_Message must have mn_ReplyPort initialized io_Device set by OpenDevice io_Unit set by OpenDevice io_Command PDCMD_QUERY (09)

Results

io_Status BIT ACTIVE FUNCTION

                 0     high   printer busy toggle (offline)
                 1     high   paper out
                 2     high   printer selected on the A1000
                              printer selected & serial "Ring
                              Indicator" on the A500/A2000
                              Use care when making cables.
                 3      -     read=0,write=1
               4-7            reserved

Bugs

In a earlier version of this AutoDoc, BUSY and PSEL were reversed. The function has always been correct.

PDCMD_SETPARAMS()

SetParams -- change parameters for the parallel device

Function

This command allows the caller to change the EOFMODE parameter for the parallel port device. It will disallow changes if any reads or writes are active or queued.

The PARB_EOFMODE bit of io_ParFlags controlls whether the
io_PTermArray is to be used as an additional termination criteria
for reads and writes.  It may be set directly without a call to
SetParams, setting it here performs the additional service of
copying the PTermArray into the device default array which is used
as the initial array for subsequent device opens. The Shared bit
can be changed here, and overrides the current device access mode
set at OpenDevice time.

IO REQUEST io_Message mn_ReplyPort initialized io_Device preset by OpenDevice io_Unit preset by OpenDevice io_Command PDCMD_SETPARAMS (0A) NOTE that the following fields of your IORequest are filled by Open to reflect the parallel device's current configuration. io_PExtFlags must be set to zero, unless used io_ParFlags see definition in parallel.i or parallel.h NOTE that x00 yields exclusive access, PTermArray inactive. io_PTermArray ASCII descending-ordered 8-byte array of termination characters. If less than 8 chars used, fill out array w/lowest valid value. Terminators are used only if EOFMODE bit of io_Parflags is set. (e.g. x512F040303030303 ) This field is filled on OpenDevice only if the EOFMODE bit is set.

Results

io_Error -- if the SetParams succeded, then io_Error will be null. if the SetParams failed, then io_Error will be non-zero.