Custom Shield - MicroSD/FRAM

Hardware
161

= DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD

Relooked at my shield over and over again and i noticed: HEY! Why isn’t the 3.3V pin soldered to the female header?! :cry:

I guess it was fine initially as there was some excess solder squeezing against the pad but the repeated plugging/unplugging broke the connection!

That’s a real headache when i do a manual via board. The Adafruit forum give me a :bulb: when they mentioned about a rough solder joint.

Time to test the microSD + FRAM working simultaneously for any problems before making the new board. HOORAY!

UPDATE

What does this screenshot say? :smile:

@Bdub and everybody, would it be recommended to have a pull up resistor on the individual CS pins?

This appnote recommends it for power up/down situations:

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Ahh cool! Love to see progress :smile:

So I can see why they think the pull up resistor is necessary, but honestly I don’t see any of the devices getting corrupted because their pins are floating… since it takes SCK MOSI CS and a particular sequence to overwrite something. The only reason might be in case the MISO connection is driven HIGH from one chip and LOW from another chip during that floating CS state. Ya know, technically you already HAVE the pull ups on there in the form of an LED and series resistor. You just need to tie the high side to 3V3 instead of SCK. I stress this is the way to go because you barely see those LEDs do anything anyway, and you need all of the PCB space you can find.

Definitely add the 0.1uF decoupling caps though. I would say those are more important.

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Actually, the read write to FRAM is too fast to notice blinking on the LED. The SD card led is helpful though :D.

Oh yes I read about the decoupling capacitor and will add them in!

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@kennethlimcp,

Now that’s the kind of “Black & White” I like seeing - Dang ! This is so AWESOME :smile:

What’s up next ? - Taking Orders ? - Kickstarter Funding ? - Help from Spark Team Supply Chain ?

Enquiring Minds want to know :innocent:

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@kennethlimcp Congrats on getting this up and running, expecially with the FRAM! I’m sure I’ll find a use for that in the near future.

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Sorry for the lack of updates!

Had a higher priority project that i had to get V1 out this week.

Decoupling Capacitors added!

@BDub, is the distance from the FRAM close enough?

TL;DR

Status of this Shield - 85% completed.

What to be done:

  1. Make sure that the FRAMs are working fine through SPI
  2. Check through once more on the Pinouts on R5 since some changes are made (D2 & D3 for CS)
  3. Add in Solder masks and label
  4. See if more pads can be added for pins for option to change pins if needed (So far, pads have been added for all CS pins)
  5. Check pin compatibility with SRAM, FLASH etc.
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167

I don't understand the question, close enough to what?

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There’s some requirement for the decoupling capacitor to be as close to the FRAM as possible right?

It’s at the bottom right of each FRAM (pin 5 - 8 side)

Opps sorry was still half awake hahaha

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When I look how small at how small @kennethlimcp SDcard board is compared to an Arduino SDcard, I come to the conclusion - Got to have one ! :smile:

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Oh yeah, so the rule of thumb is keep your decoupling caps as close to the power and ground pins of the part you are trying to decouple noise transients from. With that in mind, you could slide the ground vias down closer to pin 4 of each FRAM if you wanted to. Otherwise it looks pretty good.

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Thanks :smile:

there’s like limited space but let me see what best i can do.

I hear the manufacturing line firing up and ready to bake some cookies! PCBs i meant :smiley:

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Alternatively, they are probably short enough as-is :wink:

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HEY GUYS!

Finally some updates! Just soldered up R5 and it works right out of the box. No wrong pin-outs etc.

Just a fully functional piece! I might pop in another FRAM later but have to 1st desolder from the breakout board.

TL;DR

Status of this Shield - 90% completed.

What to be done:

  1. Make sure that the FRAMs are working fine through SPI
  2. Check through once more on the Pinouts on R5 since some changes are made (D2 & D3 for CS)
  3. Add in Solder masks and label
  4. See if more pads can be added for pins for option to change pins if needed (So far, pads have been added for all CS pins)
  5. Check pin compatibility with SRAM, FLASH etc. (halfway through this)
  6. Fabricate PCB and buy more parts!

Decoupling caps have been added in R5 but this latest prototype does not include them. No issues though! can probably send for production without worrying about that.

My next dateline i’m targeting is JUNE 2014 to have at least 10 PCBs made and tested by the :spark: Elites and we are ready to take over the world! :wink:

3 Likes
174

A man after my own heart ! Yes, you can take over the world but please do, share the Love !

Place my name on the waiting list to get a finished product.

Having the ability to easily read & write data and run html / php programs via web interface in such a small foot print - “You’re Going to Take Over the World” :innocent:

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Running websites off this is something im considering. With such a small footprint it would be ideal, and hopefully pretty powerful using the core and some good speed devices.

I was considering getting a pi, but this could maybe allow for a full webserver to be run and everything stored on the card

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176

Sorry for MIA-ing!

After all the crazy fun at Maker Faire and surviving 2.5 weeks as a freshie…

I’m working on the files for production!

1st up, pretty labels:

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I usually change all component labels to NET 25 and then make my own in LAYER 21 to display names with spaces if needed.

@BDub1 @timb what would you guys suggest for best way to mark up labling in Eagle Cad ?

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work work…

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OK DONE!!! :heart:

You cannot count the number of times i re-generated the file, check, re-do, check x 10000

This is how the teardrop looks like on the vias :smiley: (see the vias)

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180

@kennethlimcp,

Looks Awesome ! and a lot better than I could of ever done ! This sdCard will make my life a lot easier.

THANKS for developing this shield !!!

2 Likes