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Best use of SRAM in DSO design — Parallax Forums

Best use of SRAM in DSO design

nutsonnutson Posts: 242
edited 2009-07-20 12:55 in General Discussion
I am in the planning (dreaming?) stage of·a propeller controlled digital oscilloscope, with an FPGA as capture memory. The FPGA overlays·the measured signals·on·an·SVGA (text) signal·generated·by the propeller.·My·FPGA board·has 256k16 fast SRAM memory, but·I am unsure how to best use this memory.

Option 1: create an 512x512x8 bit·pixels graphics screen from it: great·for·graphics·and simulating screen persistance (in fact I am using the memory this way in another design).

Option 2: use the memory to allow 256K point capture in single shot·measurements: great for looking at serial protocols (compared to 4-8K Point·capture·with FPGA local memory)

Option 3: use the memory as·a·"digital phosphor" screen·(see tektronix publications). Allows·to·speed up·signal capture·to 10.000·waveforms/second,·great to catch glitches and anomalies in digital signals (compared to 500-1000 waveforms/sec with FPGA local memory capture).

Having no·hands on experience with modern DSO/MSO scopes, maybe more experienced designers and·DSO/MSO users can comment which option would be·more·usefull in designing and debugging propeller based projects.

Nico Hattink

Comments

  • LeonLeon Posts: 7,620
    edited 2009-07-20 12:55
    You don't really need the Propeller. The $99 Spartan 3 kit from Digilent comes with plenty of memory and a VGA connector. All you need to do in terms of hardware is to interface a high-speed ADC to it via one of the expansion connectors and plug in a 24.576 MHz oscillator module. It has a PS2 keyboard connector. Lots of people use them as low-cost logic analysers:

    www.sump.org/projects/analyzer/

    Leon

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    Post Edited (Leon) : 7/20/2009 1:02:01 PM GMT
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