ToolLink User Manual
MKS Instruments, Inc.
Page 22 of 30
18
Get/Set
Transmit Acknowledge
USINT
See Below
19
Get/Set
Max Receive Size
SHORT_STRING
Input Message Size (0-
64)
20
Get/Set
Max Transmit Size
SHORT_STRING
Output Message Size (0-
64)
21
Get/Set
Byte Swap
USINT
1 = Yes, 0 = No
Receive Data – Attribute 3
The Receive Data attribute returns data received from the serial connection with a 4-68 byte message
formatted as follows:
Status
Rx Counter
TX Acknowledge
Length
Data
Byte 0
Byte 1
Byte 2
Byte 3
Max Rx Bytes
Status:
Returns the state of the serial buffers and indicates if a parity error was found in the received
data. Status is bit-mapped as follows:
Bit 7 – RX Buffer Empty
Bit 6 – RX Buffer Overflow
Bit 5 – RX Parity Error
Bit 4 – TX Buffer Empty
Bit 3 – TX Buffer Overflow
Rx Counter:
Increments from 0-255 each time a new serial packet received by the CDN466 is placed in
the Data field.
TX Acknowledge:
Increments from 0-255 each time a complete serial message has been transmitted by
the CDN66.
Length:
The number of bytes of the serial message in the Data field.
Data:
Data received by the CDN466 from the serial connection, unused bytes are set to 0.
Transmit Data – Attribute 4
Setting the Transmit Data attribute will allow data to be sent to the serial connection, as in the I/O
command message. The Transmit Data attribute is formatted as follows:
Command
Rx Acknowledge
TX Counter
Length
Data
Byte 0
Byte 1
Byte 2
Byte 3
Max Rx Bytes
Command:
The command byte allows the data in the receive and transmit buffers to be flushed.
Bit 6 – Clear Rx Buffer (Set bit to clear)
Bit 3 – Clear TX Buffer (Set bit to clear)
Rx Counter:
If the Rx Handshaking attribute is enabled the Rx Acknowledge must be set to the value of
Rx Counter (0-255) in the Receive data attribute before the data field will be updated with a new serial
packet. Setting Rx Acknowledge to ‘0’ will reset the Rx Counter to ‘0’. If Rx Handshaking attribute is
disabled the Rx Counter is ignored and should be left at ‘0’.
