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TABLE OF CONTENTS
parallel.device/CMD_CLEAR
parallel.device/CMD_FLUSH
parallel.device/CMD_READ
parallel.device/CMD_RESET
parallel.device/CMD_START
parallel.device/CMD_STOP
parallel.device/CMD_WRITE
parallel.device/OpenDevice
parallel.device/PDCMD_QUERY
parallel.device/PDCMD_SETPARAMS
parallel.device/CMD_CLEAR parallel.device/CMD_CLEAR
NAME
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)
parallel.device/CMD_FLUSH parallel.device/CMD_FLUSH
NAME
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)
parallel.device/CMD_READ parallel.device/CMD_READ
NAME
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.
SEE ALSO
parallel.device/PDCMD_SETPARAMS
parallel.device/CMD_RESET parallel.device/CMD_RESET
NAME
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.
parallel.device/CMD_START parallel.device/CMD_START
NAME
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)
SEE ALSO
parallel.device/CMD_STOP
parallel.device/CMD_STOP parallel.device/CMD_STOP
NAME
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)
SEE ALSO
parallel.device/CMD_START
parallel.device/CMD_WRITE parallel.device/CMD_WRITE
NAME
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.
SEE ALSO
parallel.device/PDCMD_SETPARAMS
parallel.device/OpenDevice parallel.device/OpenDevice
NAME
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
exec/CloseDevice
parallel.device/PDCMD_QUERY parallel.device/PDCMD_QUERY
NAME
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.
parallel.device/PDCMD_SETPARAMS parallel.device/PDCMD_SETPARAMS
NAME
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.