Reference Manual

PMAC 2 Software Reference

PMAC On-Line Command Specification 219

All other buffers except for fixed motion programs (PROG) and PLC programs must be

deleted before PMAC will accept this command. There can be no rotary motion program,

leadscrew compensation table, transformation matrix, data gathering or stimulus buffers in

PMAC memory (any buffer created with a DEFINE command) for this command to be

accepted. It is usually best to reinitialize the card with a $$$*** command before sending

the DEFINE UBUFFER command.

The address of the end of unreserved memory is held in register X:$0F3F. This register must

hold the address $A000, signifying no defined buffers, in order for PMAC to be able to create

a user buffer. Immediately after the user buffer has successfully been defined, this register

will hold the address of the start of the buffer (the end of the user buffer is always at $9FFF).

However, after other buffers have been defined, the end of unreserved memory will not

match the beginning of the user buffer.

To free up this memory for other uses, the DEFINE UBUFFER 0 command should be used

(there is no DELETE UBUFFER command). It may be more convenient simply to re-

initialize the board with a $$$*** command.

Example

RHX:$0F3F ; Look for end of unreserved memory

008A3D ; Reply indicates some reserved

$$$*** ; Re-initialize card to clear memory

RHX:$0F3F ; Check end of unreserved memory

00A000 ; Reply indicates none reserved

DEFINE UBUFFER 256 ; Reserve memory for buffer

RHX:$0F3F ; Check for beginning of buffer

009F00 ; Reply confirms 256 words reserved

M1000->D:$9F00 ; Define M-variable to first word

M1010->Y:$9F80,12,1 ; Define M- variable to a middle word

M1023->X:$9FFF,24,S ; Define M- variable to last word