ADLINK PCI-9820 - Manual (Page 37)

Operation Theory
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the PCI-9820 also features on-board 3k-sample FIFO to achieve real-time
transfer bypassing the SDRAM, directly to host memory.
Figure 4.11 Scatter/gather DMA for data transfer
4.6 AI Data Format
Table 4.2 illustrates the ideal transfer characteristics of various input ranges
of the PCI-9820. Bit13-0 is the acquired 14-bit A/D data with binary coding
format while bit14 is the out-of-range indicator (logic “1” means out-of-range).
Description Analog Input Voltage Digital code
Full-scale Range ±5V ±1V
Least significant bit 0.61mV 0.122mV
> = FSR >= 5V >= 1V 7FFF
FSR-1LSB 4.99939V 0.999878V 3FFF
Midscale +1LSB 0.61mV 0.122mV 2001
Midscale 0V 0V 2000
Midscale –1LSB -0.61mV -0.122mV 1FFF
-FSR -5V -1V 0000
< -FSR < -5V < -1V 4000
Table 4.2 Analog input voltage and the output digital code (Note that
bit14 is the out-of-range indicator)