CY545 Stepper System Controller
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CHAPTER 3-COMMAND INTERFACES
Command Interfaces
The CY545 supports two basic command interfaces, a parallel interface and a serial interface.
These signals are similar to functions on other CYxxx controllers from Cybernetic Micro
Systems.
Parallel Interface
The parallel interface uses two handshake lines, IO_REQUEST and BUSY. When you wish to
send a command character to the CY545, you first check that it is not busy; the BUSY signal
should be high.
You then place the character to send on the parallel data bus lines. Be sure to drive all 8 data
lines.
Next, you drive the IO_REQUEST signal low,
indicating that a character is available
Now, wait for the CY545 to go busy, with a low
level on the BUSY signal, indicating that the
CY545 has read the command character.
Finally, you remove the character from the data
bus and drive the IO_REQUEST line high again.
This function is repeated until all command characters have been issued to the CY545. In direct
command mode, the CY545 executes every command as it is received. This means that the
CY545 will go busy for a longer period of time with the last character of a command, while the
command is actually executed. For long time delays or long motions, this time could be many
seconds.
This parallel interface is compatible to that of other CYxxx control chips. It is also compatible
with the CY233 Network Controller, so you can command several CY545s from a computer
serial port, using a CY233 as a network “front end” to each CY545.
CY545 Interface to CY233 Network Control Chip
For a CY233-based interface, the DAV signal from the CY233 is connected to the
IO_REQUEST signal of the CY545, and the ACK signal of the CY233 is connected to the BUSY
signal of the CY545. In addition, the FPL signal of the CY233 is connected to USRB6 of the
CY545, which shares the FPL function on this line. An example applications schematic,
provided with this manual, shows the connections. The relevant portion is reproduced below.
© 2002 Cybernetic Micro Systems
11
Chapter 3 - Command Interfaces
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