Configuring the NI-987x Baud Rate in FPGA Mode

Updated Jan 3, 2019

Reported In

Hardware

  • NI-9870
  • NI-9871
  • C Series Serial Interface Module

Software

  • LabVIEW FPGA Module

Issue Details

I am using the NI-987x module with my Compact RIO for serial communication.
  • What baud rates can I use with this module in FPGA mode?
  • How can I set the baud rate in FPGA mode?

Solution

Programatically Setting the Baud Rate

While programming in FPGA Mode, you can configure the baud rate of each port programatically with the FPGA I/O property node.

In the property node, click the element and select Baud Rate Divider and Baud Rate Prescaler. All possible baud rates are determined by the following equation: 

Baud Rate = 3686400 / (Divider * Prescaler)

Divider can be between 1 and 65535
Prescaler can be 1 or 4.
 
 

Non-Programatically Setting the Baud Rate

The baud rate for each port can also be configured in the Module Properties. 
  1. Right click on the 987x module in the Project Explorer and select Properties.
  1. Check and set the Desired Baud Rate with Divider and Prescaler values. The Baud Rate is calculated as per the above equation.
  • Note that if an entered Desired Baud Rate is outside of the possible baud rates per the above equation, the Actual Baud Rate will be a different value with a %Error.

 

 

Additional Information

When using the 987x modules with Scan Interface mode, there is a limitation of possible baud rates the user can use. For more information, please refer to the following document: NI-VISA Error Code -1073807330 When Using a NI 987x module in Scan Mode  
 

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