Topic: DIY PCB with AVALON: "The Quarter Stick" - Needs Help! - page 3. (Read 89497 times)

never did a video before. i would totally suck!
I'll make one, if you do the video editing. Cut out all the boring crap
make it interesting.

Stealing this list for my school.

Hope to get some Nanos / Quarter Sticks for students to work on.

I know this is a lot to ask but could you do a few videos on your build? That would be awesome for our students here at school to see a designer / builder go through a build.

Got all new fresh supplies for a DIY setup. Spent a little over $200.
Here is a picture of my modest setup. I plan to use these very tools to assemble some Quarter stick miners.
Hope that anyone who was borderline of trying to assemble a board themselves would appreciate this
information:



Here is my DIY list and costs:

Weller WES51 Analog Soldering Station   $84.95      
http://www.amazon.com/Weller-WES51-Analog-Soldering-Station/dp/B000BRC2XU/ref=pd_sim_hi_7


Thermal Expoxy   $8.99      
http://www.amazon.com/Arctic-Alumina-Thermal-Adhesive-Tube/dp/B0009IQ1BU/ref=pd_rhf_se_s_cp_2_3SXV


Thermal Paste   $8.22      
http://www.amazon.com/Arctic-Silver-Polysynthetic-Thermal-Compound/dp/B0002VFXFE/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1369935530&sr=1-1-catcorr&keywords=thermal+paste


Soldering Iron Tip Cleaner   $7.79      
http://www.amazon.com/Aoyue-Soldering-Cleaner-sponge-needed/dp/B005C789EU/ref=pd_sim_hi_7



Weller .015" x .000" x 1.00" Long Conical Tip   $4.95   
http://cs-sales.net/we0x0x1locot.html


Precision Tweezers Set   $18.90      
http://www.cmlsupply.com/tweezers/precision-tweezers-set-6pcs-stainless-steel.html


Kester EP256 Lead Solder Paste   $12.99      
http://www.cmlsupply.com/electronics-materials/solder-paste/kester-ep-256-syringe.html


Kester 44 Rosin Core Solder 63/37 .020" 3/4oz   $5.99      
http://www.cmlsupply.com/electronics-materials/solder-wire/kester-44-6337-020-solder-pocket-pack.html


Free Stuff   $0.00      
http://www.cmlsupply.com/free-stuff.html
I Recommend getting the ESD Tweezers
http://www.cmlsupply.com/free-stuff/tweezers-jly-05-esd.html

Organic Water Soluable Solder Flux   $5.10      
http://www.digikey.com/product-detail/en/83-1097-2331/KE1808-ND/365532


Solder Wick Size#1   $4.30   
http://www.digikey.com/product-detail/en/80-1-5/80-1-5-ND/306980

         
Digital Multimeter   $35.82       
http://www.newark.com/tenma/72-7735/multimeter-digital-handheld/dp/02J5540
Meter is good for checking for shorts especially between power planes. It can also be used
to measure resistive and capacitive component values. Some DIY kits make come with
components that are not marked and it is critical to have an instrument that those values
can be discovered.
         
Materials Obtained Locally         
Skillet, Hot Plate, or Pan         

Solder Paste Squeegee: Use a hard plastic card or old credit card. I prefer using a razor blade to reduce the amount of rework: http://www.vansonink.com/products/Razor-Blades-%239-single-blade-%28100%29.html

Aluminum Foil         

Distilled Water   

Firm Nylon Bristle Brush (Grout Brush)

Cleaning Agent: (one or some of the following)   
           409 Cleaner (My favorite)   
           Flux Remover (not necessary, but good for stubborn Flux)
           Alcohol (not necessary)   
           Acetone (not recommended; educate yourself on this chemical; good for stubborn Flux)

Two Squirt Bottles: (one for Distilled water and the other for a cleaning agent)
make sure the bottle is chemical resistant if acetone is used. Use a lot of protective
gear (gloves, goggles, good ventilation) if using acetone. Again, not recommended, but does a good job if cleaning flux that has been baked into the board at a high temperature. If done right, this should
not happen.

Compressed Air (Can of air from your local store works):
used to dry off the board after cleaning. Helps remove any contaminants that may
still be in the water on the PCB.
   
Other:
1)Steady Hand      
2)Good Eyes      
3)Lots of Time      
4)A ton of Patience      
5)Willing to screw up a couple boards in the process of learning a new skill.
Actually, rework is very possible for a few more modest tools. But that is for
a different post.      

Ok:)

Sometime between early and late June. Maybe. Sort of. If the gods be willing.

That's why the NOR gate is there. It extracts the clock from the data lines so that the UART can use synchronous slave mode to pull in the data. It has a 2 char FIFO that means an interrupt can be used to read byte size data to a 4 byte word, ready to forward via USB. I hope you know this is giving away my "trade secrets", ha ha. Kidding, because I already posted this in the K1 thread a while ago. "It came to me in a dream".

hi guys


when are you suppose to get the chips?

So you got 12 cycles for reading in the data then when 'REPORT_x'
is clocked at 4 Mc. Did you connect it to an interrupt pin or a
timer/capture pin? Or just polling the lines?

intron

I know in my design it runs at 48MHz. Off hand I don't know about others but probably the same for allten.

And do you know at what frequency the MCU is ticking?

intron

It doesn't explicitly say so I'd expect it uses the same 250nS period as input data. That would be the input clk/4 which is convenient. Since the PLL gives a lot of flexibility in generating the hash clock I wonder if providing a 16MHz clock would result in 500nS. It's not documented except that it indicates valid config values allow a 16MHz master clock. I should have ordered a couple extra oscillator frequencies to experiment. I will be testing the comparably jittery PIC clock at some point just to see.

And at what clock frequency? No hints in the datasheet.

Definitely internally clocked as it must send the nonce when it is found and not later when new work is pushed.

And do you know how these 'REPORT_x' lines are clocked? The datasheet is
not very conclusive. Are the driven by the 'CONFIG_xI' lines or by some
own , internal clock? And if so, at what frequency?

From the Avalon datasheet:

"AVALON will send out the nonce value only when it get shares. ..."

This would suggest the nonce is clocked out with the same frequency
new work is clocked in via 'CONFIG_xI'. But not sure.

intron

You use a NOR gate to merge the 'REPORT_x' signals and feed the
resulting signal to the MCU. In the Avalon ref design the use two
non-inverting buffers. You do this on purpose I guess?

intron

Well, I ended up adding a pull down. Better to have it and not need than not have it and need it :-)
Thanks for pointing it out.

I don't think the reset will be an issue..but who knows.. guess we find out when you get a chip to test.

Update:
Schematic is complete
BOM is complete
Parts are on their way.
Board Layout is complete.

Ordering Boards and Stencil in about 5 days.

About the design for the DIY Open Source "Quarter Stick" Miner:
There was a lot of redundancy added to the board. The rationale is it
is easier to fix a board cut too long vs. a board cut to short. This increases the
likelihood of the first revision working out. Decreasing costs is then just a
matter of not installing components that are not needed. The power supply
was designed to go easy on the USB port as well. USB ports were not engineered to supply
power 24/7 at their max current so this feature is important.
Heatsink is 28mmx28mm
Larger PCB with additional component spacing to be DIY friendly.
External Power feature added
I2c for interconnecting boards and using just one as the USB is now possible as well.
Total Board costs + Components looking to be around $12.00 (doesn't include shipping, taxes, Avalon chip; bulk orders of 1000+)

daemondazz and ProfMac,

Thanks for the offer. I'm really hoping to push this to the finish line ASAP.
5 to 10 days max.

Shoot me an email on what days you could work on it and at what times.

Thanks for the feedback.
The capacitance seen by the USB port should be 4.7uF, but probably a bit more.
Won't know exactly until I have one in hand to test.
Should work though as I've done other USB designs similar to this that have worked fine, but
the DCDC converter is a first for me.

I can't guarantee is will be in reset. How critical do you think it is?
There will be a delay before the 1.2V signal will be ready; it will
be in reset before then.