National Instruments NI 6225 - Chapter 10 Bus Interface; DMA Controllers and USB Signal Stream

© National Instruments Corporation 10-1 M Series User Manual
10
Bus Interface
The bus interface circuitry of M Series devices efficiently moves data
between host memory and the measurement and acquisition circuits.
M Series devices are available for the following platforms:
•PCI
• PCI Express
•PXI
• PXI Express
•USB
All M Series devices are jumperless for complete plug-and-play operation.
The operating system automatically assigns the base address, interrupt
levels, and other resources.
NI M Series PCI/PCIe/PXI/PXIe devices incorporate PCI-MITE
technology to implement a high-performance PCI interface. M Series USB
devices incorporate USB-STC2 technology to implement a Hi-Speed USB
interface.
DMA Controllers and USB Signal Stream
NI M Series PCI/PCIe/PXI/PXIe devices have six fully-independent DMA
controllers for high-performance transfers of data blocks. One DMA
controller is available for each measurement and acquisition block:
• Analog input
• Analog output
• Counter 0
• Counter 1
• Digital waveform generation (digital output)
• Digital waveform acquisition (digital input)
Each DMA controller channel contains a FIFO and independent processes
for filling and emptying the FIFO. This allows the buses involved in the
transfer to operate independently for maximum performance. Data is