Operation Theory
49
Figure 4-8: DIREQ as input data strobe (Falling Edge Active)
Note
:
From the timing diagram of external clock mode, the maxi-
mum frequency can be up to 40MHz. However, users should
note that when the sampling frequency of digital input is
higher than the PCI bus bandwidth (33Mhz), or the band-
width of chipset (30Mhz typically) from PCI bus to system
memory. Users should check the overrun status when the
DMA block size is larger than 16K samples. If overrun al-
ways happens, users should reduce the DMA block size or
slow down the sampling frequency. For example, the DMA
block size should be smaller than 64K when the external
clock is 40Mhz in the DOS Operation
4.10.3 Digital Input DMA in Handshaking Mode
For digital input, through DI-REQ input signal and DI-ACK output
signal, the digital input can have simple handshaking data trans-
Summary of Contents for cPCI-7300A
Page 4: ......
Page 10: ...vi List of Figures...
Page 18: ...8 Introduction...
Page 21: ...Installation 11 2 4 cPCI PCI PCIe 7300A Layout Figure 2 1 PCI 7300A Layout Diagram...
Page 26: ...16 Installation Figure 2 4 CN1 Pin Assignment...
Page 100: ...90 C C Libraries BufNotDWordAlign DMADscrBadAlign...
Page 108: ...98 C C Libraries...
Page 114: ...104 Appendix...