Hello,
First it is necessary to have both devices properly configured in MAX or T&M. Remember that the User Manual of your VME device will let you know what are the allowed Base Addresses that you can use, and then you need to enter those numbers in MAX.
Some VME devices will require for you to set the base address that you want to use in a set dip-switches, and some other VME devices not let you choose and will give you a specified base address that you need to use.
Please follow the links below for more information:
*
"how can i configure my vme device?"*
"add a fictitious VME device?"Now, when writing and reading from your device you can use either VXI or VISA function calls. VISA uses relative addressing, and VXI uses absolute addressing. So what does this mean?
When using VISA calls (such us viIn or viOut) you will need to provide the offset of your register respect to the base address. As explained in the link
"address", if you need to write data to register 0x3804, you will need to call the function viIn with offset 4, because VISA already knows that the base address is 0x3800 (because that's what you entered in MAX or T&M).
When using VXI function calls, if you need to write data to register 0x3804, you will need to enter the absolute register address to the vxi
In function call.
Hope this helps,
Claudia Lorente
Applications Engineer
National Instruments
http://www.ni.com/ask
