Chapter 2
NI 5450 Overview
NI PXIe-5450 User Manual
2-46
ni.com
Onboard Memory for Multichannel
Waveform Generation
On multichannel devices, onboard memory is allocated separately for each
configured channel. When you write a waveform to the onboard memory
of a multichannel device, the space required for the waveform is allocated
in the onboard memory for each channel.
You can write different data to the waveform allocated for each channel, as
long as the data written requires the same amount of memory on each
channel. For example, Waveform 1 can contain a ramp wave on channel 0
and a square wave on channel 1, as shown in the following figure.
Waveform and Generation Instruction Memory Size
Waveform Memory Size
Waveforms are stored in the NI 5450 onboard memory in contiguous
blocks. These blocks are allocated in multiples of 128 bytes. This allocation
style means that while waveform sizes may be multiples of two samples
(four bytes) on the NI 5450, the amount of onboard memory allocated for
each waveform is a multiple of 128 bytes. The following figure represents
the total memory of a device and shows memory that was initially empty,
but it now has multiple waveforms written to it, nearly filling the device
memory.
Waveform
2
Waveform
1
Free
Memory
Waveform
4
Channel 1
Waveform
3
Waveform
2
Waveform
1
Free
Memory
Waveform
4
Channel 0
Waveform
3
