DS588 Datasheet, PDF (10/24 Pages) Xilinx, Inc – Programmable interrupt generation

XPS Delta-Sigma Digital to Analog Converter (DAC) (v1.01a)
PLB Interface Module
PLB Interface Module provides bidirectional interface between Delta-Sigma DAC IP core and the PLB.
The base element of the PLB Interface Module is slave attachment, which provides the basic
functionality of PLB slave operation.
Interrupt Service Controller
The Interrupt Service Controller is a continuation of the Xilinx family of IBM CoreConnect™
compatible LogiCORE products. It provides interrupt capture support for the connected IP function.
Interrrupt Service Controller provides the following functions:
• Parameterized number of interrupts needed by the IP.
• Provides both Interrupt Status Register (ISR) and Interrupt Enable Register (IER) functions for the
user IP.
Flow Description
The following is a brief discussion on setting the DAC registers to initiate a D/A conversion.
To generate a analog value:
1. Write the data to be converted into the Data FIFO.
2. Enable the DAC by writing a "1" to the control register.
3. Drive Read_en high for one SPLB_Clk, the value written into the Data FIFO will start being
converted.
4. If a new value is needed, write the new value into the Data FIFO.
Applications of DAC
This section lists some of the applications for the XPS Delta-Sigma DAC.
• Programmable Voltage Generator: A variable voltage between 0 V and V_CCO can be generated
with a granularity determined by the bus width of DACin. In these applications, the voltage
typically does not change quickly, so RC may be large to minimize noise.
• VREF Generator: This is a specific application of a Programmable Voltage Generator. For some
SelectIO receivers standards, a reference voltage is required for each bank of receivers. If a DAC is
used to generate this voltage, V_REF can be dynamically changed to verify operating margins when
conducting system tests. See the Xilinx application note XAPP133 (Using the Virtex SelectI/O
Resource) for more information on selectIO.
• Waveform Generator: Various analog waveforms, such as sine, sawtooth, triangle, etc., can be
created by sequentially feeding the proper values to DACin. The values are normally pre-stored in
SRAM. Block SelectRAM+ is ideal for this purpose. See Xilinx application note XAPP130 (Using
the Virtex Block SelectRAM+ Features) for more information on Block SelectRAM+.
• Sound Generator: Delta-Sigma DACs are widely used in sound reproduction, speech synthesis,
etc. Since the analog output is changing rapidly, RC must be chosen with an acceptable trade-off
between noise and frequency response.
• RGB Color Generator: Although Delta-Sigma DACs are too slow to directly generate Red-Green-
Blue signals for a raster display, they are applicable in some color generation systems that do not
operate in real time.
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DS588 December 2, 2009
Product Specification