CY325 ETC, CY325 Datasheet - Page 17

• Manufacturer Part Number: CY325
• Description: Stepper System Controller
• Manufacturer: ETC

CY545 Stepper System Controller
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The CY233 Network Control chip allows you to connect up to 255 devices to a single RS-232
serial communications line such as an IBM-PC COM1 or COM2 port, with unique addresses
assigned to each device. The CY233 Network is ideal for distributed systems where central
control is required but very high speed communication is unnecessary.
The CY545 Serial Interface
The CY545 also provides a direct serial command interface, which may be connected to a host
computer or terminal. Since the CY545 signals are all TTL voltage levels, external RS-232 line
drivers and receivers must be provided, to translate the RS-232 voltage levels to the CY545
TTL levels. A Maxim MAX-233 does this function in a single chip, operating at +5 volts. This
interface is also shown on the applications schematic.
The serial interface may be operated in one of two ways, with a fixed baud rate, selected at
power up, or with an adaptive baud rate, selected by two carriage return characters from the
host.
The fixed baud rate mode is selected by tying the BUSY line low, so the CY545 will read it as a
zero value on power up. The CY545 IO_REQUEST line value will determine the baud rate as
follows:
© 2002 Cybernetic Micro Systems
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Chapter 3 - Command Interfaces