Maximum Value of xferdata() Length Parameter - KBA84124

Version: *A

 

Question:

What is the maximum value of the xferdata() length parameter in CyAPI.lib/CyUSB.dll?

 

Answer:

You can calculate the maximum value of the xferdata() length parameter or any other parameter in CyAPI.lib and CyUSB.dll by referring to the corresponding programmer’s reference guide. However, the maximum value of the parameter changes if it is restricted by USB protocol or the OS environment. In CyAPI.lib the length of transfer is defined as LONG and in CyUSB.dll it is defined as int, which means it has a size of 4 bytes. The maximum value is 0x7FFFFFFF.

Install SuiteUSB to get the programmer’s reference guides. The reference guide for CyAPI.lib is available at C:\Program Files\Cypress\Cypress Suite USB 3.4.1\CyAPI and the reference guide for CyUSB.dll is available at C:\Program Files\Cypress\Cypress Suite USB 3.4.1\CyUSB.Net. The file paths may vary depending on your installation method.

Note Though these parameters are not restricted, large transfers are not recommended.