pattern output

[Vishal]

hello friends,ihave some more doughts related to pattern output.So please help me related to that topic.
My questions are as below.
1.) In pattern output let's first talk about finite output.
Bydefault 6534 preload the onboard memory before output data right? If i am doing finite output operation & my data size is less than 32 MB then it's ok. But what will happen if my data size is greater than 32 MB?I want to know the exact sequence in which the process will occur.
As per me, 6534 will preload up to 32 MB first- starts to output and now get more data from pc buffer - am i right? please explain briefly.
2. ) Similarly in continuous pattern output will it preload first or not?
3.) while using onboard looping,if i am using data less than32MB,6534 wil
l first preload memory & then starts repeatative output. But what will happen if i give buffer size greater than 32MB? Will it show error or it will overlap the onboard memory after 32 MB? Please remove my confusion.

[JustinBritten]

Vishal,

1. You are correct. The FIFO is 32MB and this will be filled with data. The remaining data in your PC buffer will be DMA- or interrupt-transfered to the FIFO in segments before being output from the board.

2. Yes, it will try to fill the FIFO first. You may view flow charts for a finite and continuous acquisition starting on page 2-24 of the 653x User Manual. Please take a look at Figures 2-12 and 2-12.

3. If you look on page 2-9 of the 653x User Manual under the heading "Continuous Output" you will find that there are two methods for outputting your data. You can have the device allow regeneration of data though the oldDataStop parameter in the DIG_DB_Config
function or the Data Overwrite/Regenerate parameter in the Digital Buffer
Control VI, called by the DIO Start VI. In this mode you will be transferring data from PC memory to the onboard memory and speeds will now be limited by the bus. As you are aware bus speeds are not a restriction when you are transferring under 32MB and performing onboard looping.

653X User Manual
http://digital.ni.com/manuals.nsf/websearch/EDE443F5C700373A862569B90072D26F?OpenDocument&node=132100_US

Regards,
Justin Britten

Applications Engineer
National Instruments