EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Citizen on July 12, 2013, 10:46:34 pm
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Hi there:)
Remember this thread over here?
https://www.eevblog.com/forum/projects/new-project-analog-acquisition-board/ (https://www.eevblog.com/forum/projects/new-project-analog-acquisition-board/)
Probably not :)
Here is the short summery:
The Acquisition Module is an addon Module for any Dev- Board that need high speed ADC but doesn't have any(like the most of them). Especially high speed FPGA boards sometimes need a high speed analog frontend for data acquisition. Like my Altera DE1 FPGA.
So i started to design my own acquisition module 8)
Here are specs for this prototype:
3xADC08200 =200MSPS, 8bit ( will be overclocked to 250MSPS)
3xDAC5311 = one DAC for each ADC. It is generating the Vref-Top, the reference voltage for ADC. So if your signal has max. Value of 1.5 V, you can set the reference voltage to use the whole 8 Bit resolution.
The main CLK-Source is Fox electronics 250 Mhz Oscillator. Its is very expensive! ( 80 € or so) But considering i got it as sample...;)
The data Acquisition /Preprocessing and so on will be done by Altera CPLD MAXII. It also controls ADC/DAC , and generate CLK for ADC ( so you can choose from 250,125,62.5 and 31.25 Msps in order o spare some energy)
You also have 7 Blue LEds to play with:P
The A-Module has ca. 48 GPIO so even if you assign all 3x8 bit channels , you will still have 24 GPIO for your special features;)
Speaking of features, you can always upgrade the CPLD-Firmware to fit your project via JTAG. My Current Firmware takes about 300 LE, so you still have 270 free LE to play with.(or you write your own from scratch:) )
The current firmware allows the user to change the configuration like samplerate, Vref's, switch ADC on/off via simple 2-Wire interface, it makes this module completely autonomous, so it can be used with any kind of Dev. Boards, even with arduino;)
The PCB has 4 layers: Signal, GND, Vcc,Signal.
Now, i am glad to show you my first prototype assembled last night.
It has some FAILS like wrong footprint for voltage regulator ( not a big problem through) and i forgot 4 Vias for bypass caps....what a noob. But i could fix it with copper wire. Also my hand soldering it not the first class, but considering this is my first project and first PCB-Design in my life, i still consider it as success:))
Now it is running a simple LED-Counter, the main Firmware is almost done and will be tested this weekend.
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Nice job. :-+
Probably you can design out most or all of the tantalums. Most people avoid them unless there is absolutely no choice. Ceramics have come a long way.
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Very Nice.
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Especially nice for a first effort! I've seen much worse from seasoned 'professionals'!