I want to check all functions of PCI 6534.I have read the user manual..I have some memory related questions.Please help me for that.

[Vishal]

I want to check all functions of PCI 6534.I have read the user manual..I have some memory related questions.Please help me for that.
1.)If i am using the continuous output mode.and the size of generated data is less than 32 MB.If i want to preload the memory,what should i do?I want that first of all i load all my data to onboard memory & then i want to make start the transfer between 6534 & peripheral.Is it possible?As per me it should be.Plz tell me how should i do this?I think that in normal procedure the transfer between 6534-peripheral & outputting data from pc buffer to onboard memory works parallely.But i don't want this.Is it poss
ible?
(2).Similarly in finite input operation(pattern I/O) is it possible to preload the memory and then i read it?Because i think that the PC memory will be loaded automatically when 6534 acquires the data and then when we use DIO read vi the pc buffer data will be transferred to application buffer.If this is true,i do not want this.Is it possible?
(3) One more question is there if i am using normal operation onboard memory will be used bydefault right?Now if i want to use DMA and if i have data of 512 bytes to acquire.How will it work and how should i do it?Please tell me the sequence of operations.As per my knowledge in normal DMA operation we have 32 Bytes FIFO is there so after acquisition of 32 bytes only i can read it.How it will known to me that 32 bytes acquisition is complete?Next,If i want to acquire each byte separately using DMA interrupts what should i do?Provide me the name of sourse from which i can get details about onboard memory & DMA process of 6534 specifically
.
(4).In 6534 pattern Input mode,if i want to but only 10 bits of data.and i don't want to waste any data line what should i do?

[rgharrison]

Hi Vishal,

I'll try to answer your questions as best I can.

1) It is definitely possible to preload data to the 32MB memory (per group) and start the acquisition after you have preloaded the memory. There are example programs on ni.com/support under Example Code for pattern generation and the 6534 that demonstrate which functions to use for this. Also, if your PC memory buffer is less than 32MB, it will automatically be loaded to the card. If you are in continuous mode however, you can choose to loop using the on-board memory or you can constantly be reading the PC memory buffer as you update it with your application environment.
2) Yes, your data will automatically be loaded into the card's onboard memory. It will however be transferred as quickly as possible to the DMA FIFO on the card and then transferred to the PC memory buffer through DMA. It is not going to wait until the whole onboard memory is filled before it transfers. It will transfer throughout the acquisition process.
3) Vishal, searching the example programs will give you many of the details of programming this type of application. I don't know you application software so I can't give you the exact functions but it is easiest to look at the examples on the net (or the shipping examples with your software). Now if you are acquiring 512 bytes of data, you will start to fill your onboard memory and at the same time, data will be sent to the DMA FIFO. When the FIFO is ready to send data to the PC memory buffer, it will (the exact algorithm is dependent on many things regarding how large the DMA packet is etc.).
4) If I understand you correctly, you want to know if you waste the other 6 bits if you only need to acquire on 10 lines. The answer to this is Yes. Although you are only acquiring 10 bits, it is acquired as a complete word (16bits) and packed and sent using DMA. You application software (NI-DAQ driver) will filter out the last 6 bits of non-data.

Hope that answers your questions. Once again, the example code on the NI site is a great place to start this type of project. Have a good day.

Ron

[Vishal]

hye Ron, first of all thank you very much for the answers.
Some new questions has been arised from your answers and that are.
1. in first answer you had tod that it's possible to preload the onboard memory before acquisition starts. And in the second answer you are teling that 6534 will pass the acquired samples as quick as possible to PC buffer via DMA FIFO. So here preloading onboard memory is not possible. Please clear my confusion. How is it possible to preload onboard memory before acquisition?

[rgharrison]

Hi Vishal,

You will only be able to preload memory if you are doing an output operation and the buffer size is less than 32MB (6534).

If you are doing digital input, you obviously can't preload the data. Once the digital input operation starts you will be transferring data as quick as possible from the onboard FIFO to the PC memory (buffer). But once again, you can't preload for an input operation.

Ron