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Monthly Archives: September 2010
Gigabit Ethernet on the ML605
One of the main reasons I chose the ML605 over a less expensive spartan6 development board was the built-in hard tri-mode ethernet MAC. The ML605 supports a variety of links between the MAC and the M88E1111 PHY on the board. … Continue reading
Posted in Embedded
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Important Power Supply Nuances
One of the more interesting and frustrating issues is that of power supply sequencing. Power supplies generally are analyzed for startup issues, but less often for other sequences of events. This can lead to interesting failures.
Posted in Analog
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SysACE on the ML605
Having gotten linux to run on my ML605, I next decided to get the compact flash card working. The compact flash card itself is actually connected to a SysACE controller, which is then connected to the FPGA.
Posted in Embedded
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Basic Linux on ML605
One of the things I had wanted to try out with my ML605 was EDK and embedded linux. Xilinx provided a basic system with (partial) built-in self test features. There was also a guide at xilinx.wikidot.org. I chose to use … Continue reading
Posted in Embedded
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Negative Gain Single OpAmp Biquad
Previously, I had written about an elegant circuit — the positive gain, single opamp biquad. That circuit is rewarding to analyze, as it has multiple nice solutions. The negative gain version is a bit more difficult to analyze. Further, it … Continue reading
Posted in Analog
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Variables and Simulations
I typically design my VHDL components for ease of reuse. I like things that are easy to read/write and infer a clear structure. As such, I try to avoid variables as much as possible. This is because VHDL doesn’t allow … Continue reading
Sallen-Key Analog Filters
Of all circuits, the one that has most influenced me is the 2nd order “biquad” using one opamp. This is commonly called the “Sallen-Key” biquad. This was the circuit I tried to understand and explain before even taking a class … Continue reading
Posted in Analog
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Synthesizable Procedures
VHDL offers a procedure language construct. Like most tools, it has a handful of advantages and disadvantages. Procedures have long been used in simulations to allow complex logic sequences to be represented as a single statement. This allows the sim … Continue reading
Posted in VHDL
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Unconstrained Vectors
VHDL makes heavy use of types, and has a concept of an unconstrained vector. This is a vector whose dimension isn’t specified in the declaration of a construct, but is determined by the instantiation or use of the construct.
VHDL Generics
VHDL has fairly good support for generics. VHDL-2008 will actually provide several improvements as well. Generics are a good alternative to code generation, and work well for the vast majority of designs. Generics aren’t a complete replacement for code generation … Continue reading
Posted in VHDL
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