Measurement Computing Personal488 rev.3.0 For DOS & Windows 3.Xi User Manual

Page 351

15B. Driver488/SUB, W31, W95, & WNT

III. COMMAND REFERENCES - 15. Command References

III-336

Personal488 User’s Manual, Rev. 3.0

The

OutputX

command sends data to an interface or external device. The Remote Enable (

REN

) line is

first asserted if Driver488 is the System Controller and

AutoRemote

is enabled. Then, if a device

address (with optional secondary address) is specified, Driver488 is addressed to Talk and the specified
device is addressed to Listen. If no address is specified, then Driver488 must already be configured to
send data, either as a result of a preceding

OutputX

command, or as the result of a

Send

command.

Terminators are automatically appended to the output data as specified.

The

forceAddr

flag is used to specify whether the addressing control bytes are to be issued for each

OutputX

command. If the device handle refers to an interface,

forceAddr

has no effect and

command bytes are not sent. If the device handle refers to an external device and

forceAddr

TRUE

Driver488 addresses the interface to Talk and the external device to Listen. If

forceAddr

FALSE

Driver488 compares the current device with the most recently addressed device on that interface. If the
addressing information is the same, no command bytes are sent. If they are different,

OutputX

acts as

if the

forceAddr

flag were

TRUE

and sends the addressing information.

The

terminator

is a pointer to a terminator structure that is used to set up the input terminators. This

pointer may be a null pointer, requesting use of the default terminators for the device, or it may point to
a terminator structure requesting no terminators. The

async

is a flag that allows asynchronous data

transfer. If this flag is

TRUE

, the

OutputX

command returns to the caller as soon as the data transfer is

underway and can be completed under DMA and/or interrupts.

FALSE

indicates that the

OutputX

command should not return until the transfer is complete. The

compStat

is a pointer to an integer

containing completion status information. A null pointer indicates that completion status is not
requested. In the case of an asynchronous transfer, this pointer must remain valid until the transfer is
complete.

Additional Output Functions

Driver488 provides additional

Output

functions that are short form versions of the

OutputX

function.

The additional

Output

functions are:

Output

OutputN

OutputMore

, and

OutputNMore

. These

functions are discussed in detail below:

Output

SYNTAX

long pascal Output(DevHandleT devHandle,char *data);

REMARKS

Output

is equivalent to the following call to

OutputX

OutputX(devHandle,data,strlen(data),1,1,0L,0,0L);

The

Output

function passes the device handle and a pointer to the data buffer to the

OutputX

function. It determines the size of the data buffer provided by the user and passes that value as the

count

parameter. It specifies that the

forceAddr

flag is set

TRUE

, which causes Driver488 to address

the device if an external device is specified. The default terminators are chosen by specifying a

pointer as the

terminator

parameter. Synchronous transmission is specified by sending

for the

async

parameter, and the completion status value is ignored by sending a

for the

compStat

pointer.

OutputN

SYNTAX

long pascal OutputN(DevHandleT devHandle,char *data,long

count);

REMARKS

OutputN

is equivalent to the following call to

OutputX

OutputX(devHandle,data,count,0,1,0L,0,0L);

The

OutputN

function passes the device handle and a pointer to the data buffer to the

OutputX

function. It specifies that the

forceAddr

flag is set

TRUE

, which causes Driver488 to address the

device if an external device is specified. The default terminators are chosen by specifying a

pointer

as the

terminator

parameter. Synchronous transmission is specified by sending

for the

async

parameter, and the completion status value is ignored by sending a

for the

compStat

pointer.

OutputMore

SYNTAX

long pascal OutputMore(DevHandleT devHandle, char *data);

REMARKS

OutputMore

is equivalent to the following call to

OutputX