CY545 Stepper System Controller
www.ControlChips.com
For these commands, the bit value parameter is treated as follows:
00H to 07H
08H to 0FH
10H to 17H
18H to 1FH
80H to 0BFH
Test one of user bits 0 to 7 for 1
Test one of data bus bits 0 to 7 for 1
Test one of user bits 0 to 7 for 0
Test one of data bus bits 0 to 7 for 0
Test user bits 0 to 5 for a group match
Both commands compare the value of the I/O signal to the value specified by the parameter.
Note that USRB0 to USRB5 can be treated as a single group of six bits, with the value test
comparing all six bits to the lower six bits of the parameter. Any other bits can only be tested on
an individual basis.
The Til command will jump to the specified byte address until the signal(s) match the parameter
value, either a low or high level. When there is a match in value, the Til command does not take
the jump, and execution falls through to the command after the Til command.
The Til command is only used in an external memory program, since it will jump or fall through,
depending on the bit value. The address of the jump is a single byte, limiting the jump to an
address on the same 256 byte page as the command after the Til command. The TIL command
may jump to itself.
The Wait command simply waits for a match of the bit(s) against the parameter value. When
there is no match, the CY545 stays in the Wait command, and continually tests the signals until
a match occurs. Once a match is detected, the CY545 will continue with the next command.
If you issue a new command either in parallel or serial format while the CY545 is stuck in a Wait
command, the CY545 will abort the
Wait function and act on the new
Y 100<cr>
E<cr>
Program start address.
command. This is a mechanism for
breaking out of Wait commands that
are stuck because the proper bit
pattern does not occur.
Next instructions go into memory.
W 1<cr>
Wait til USRB1 = 1.
+ <cr>
G<cr>
/B 2<cr>
W 11h<cr>
Go (200 steps by default).
Drive USRB2 = 0 as signal.
Wait til USRB1 = 0.
The Wait command is normally used
in an external memory program, to
synchronize the CY545 with some
external control or status signal. For
example, move a part into place,
activate some operation by changing
a user bit, wait for a signal back from
the operation indicating operation
complete, then remove the part.
– <cr>
G<cr>
B 2<cr>
Return same number of steps.
Drive USRB2 = 1 again.
T 10h,100<cr> Test USRB0 & jump unless it is 0
0<cr>
then fall thru and stop the program
by returning to command mode.
Q<cr>
Y 100<cr>
X<cr>
End of program definition.
Reset the address.
eXecute the above program.
The example illustrates the use of
Wait and Til commands for the
operation described above:
© 2002 Cybernetic Micro Systems
23
Chapter 6 - Bit Function Commands
ETC [ ETC ]
