Purpose: Check if <STOP> key is pressed
Call address: $FFE1 (hex) 65505 (decimal)
Communication registers: A
Preparatory routines: None
Error returns: None
Stack requirements: None
Registers affected: A, X
Description: If the <STOP> key on the keyboard was pressed during a UDTIM call, this call returns the Z flag set. In addition, the channels will be reset to default values. All other flags remain unchanged. If the <STOP> key is not pressed then the accumulator will contain a byte representing the lost row of the keyboard scan. The user can also check for certain other keys this way.
How to Use:
EXAMPLE:
JSR UDTIM ;SCAN FOR STOP JSR STOP BNE *+5 ;KEY NOT DOWN JMP READY ;=... STOP
This page has been created by Sami Rautiainen. | |
Read the small print. | Last updated December 17, 2002. |