Chapter 10: Digital-To-Analog Converter (Dac); Spi Communication - Xilinx Spartan-3A User Manual

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Digital-to-Analog Converter (DAC)
The Spartan-3A/3AN Starter Kit board includes an SPI-compatible, four-channel, serial
Digital-to-Analog Converter (DAC). The DAC device is a Linear Technology LTC2624
quad DAC with 12-bit unsigned resolution. The four outputs from the DAC appear on the
J21 header, which uses the Digilent six-pin
header are located immediately below the Ethernet RJ-45 connector, as shown in
Figure

SPI Communication

As shown in
digital values to each of the four DAC channels. The SPI bus is a full-duplex, synchronous,
character-oriented channel employing a simple four-wire interface. A bus master—the
FPGA in this example—drives the bus clock signal (SPI_SCK) and transmits serial data
(SPI_MOSI) to the selected bus slave—the DAC in this example. At the same time, the bus
slave provides serial data (SPI_MISO) back to the bus master.
Spartan-3A/3AN Starter Kit Board User Guide
UG334 (v1.0) May 28, 2007
10-1.
6-pin DAC Header (J21)
Figure 10-1: DAC and Associated Stake Pin Header (J21)
Figure 10-2, the FPGA uses a Serial Peripheral Interface (SPI) to communicate
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Chapter 10
Peripheral Module format. The DAC and the
Linear Tech LTC2624 Quad DAC
SPI_MOSI: (AB14)
SPI_SCK: (AA20)
DAC_CS: (W7)
DAC_CLR: (AB13)
DAC_OUT: (V7)
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