Jump to content

[Version 1] Sdcard And 3.3v Regulator


Recommended Posts

Hi everyone,

I have a question about the Teensy and the SDcard.

Back in June, I have soldered the SDcard Adapter onto the Teensy WITHOUT the 3.3V regulator and it worked fine but then I found on the pjrc.com site that a 3.3v regulator can be used on the Teensy with the SDcard adapter to "protect the SDcard." My question is is the 3.3V regulator NECESSARY? In the long run, will the 5V damage the SDcard and the Teensy? Right now, the teensy has the SD card adapter and works fine so far. Thanks.

Bits1

Link to post
Share on other sites
I would think that if it is working fine you don't need it. But looking at this the Operating Voltage of a SD card is 2.7V-3.6V. So if you want to protect your card then put it on.

Thank you for answering my question. I looked at the pjrc.com site and it stated "A 3.3 volt regulator and buffer chip allows using Micro SD cards with 5 volt systems. " I assume that the buffer chip is already SOLDERED on the SD card adapter? If it is true, then I suppose that will be alright? >.<

Bits1

Link to post
Share on other sites
Just looked on the pjrc website at the sd card page (couldn't find it last night) and the regulator and buffer are fitted to the sd card adapter so you don't have to fit one.

Thank you so much, you are AWESOME!

Bits1

Link to post
Share on other sites
Hi everyone,

I have a question about the Teensy and the SDcard.

Back in June, I have soldered the SDcard Adapter onto the Teensy WITHOUT the 3.3V regulator and it worked fine but then I found on the pjrc.com site that a 3.3v regulator can be used on the Teensy with the SDcard adapter to "protect the SDcard." My question is is the 3.3V regulator NECESSARY? In the long run, will the 5V damage the SDcard and the Teensy? Right now, the teensy has the SD card adapter and works fine so far. Thanks.

Bits1

Hi,

I've been playing with the Teensy and would like to move to using the SD Adapter that I purchased. While I am an experienced programmer, soldering and reading schematics is somewhat new to me. I've look at the schematics on the pjrc website, but I am unsure of the mapping of the SD pins to the Teensy pins (other than the voltage). For example, what pin on the Teensy does the SW pin from the SD map to?

Any help would be appreciated.

Thanks!

Link to post
Share on other sites
Hi,

I've been playing with the Teensy and would like to move to using the SD Adapter that I purchased. While I am an experienced programmer, soldering and reading schematics is somewhat new to me. I've look at the schematics on the pjrc website, but I am unsure of the mapping of the SD pins to the Teensy pins (other than the voltage). For example, what pin on the Teensy does the SW pin from the SD map to?

Any help would be appreciated.

Thanks!

Hi Grayson5.

I have also ordered the micro sd card adapter for the teensy. and am planning on soldering to the teensy 2.0

not the ++ model. because It is easier to do on the teensy 2.0.

disregard the schematics on the http://www.pjrc.com/teensy/sd_adaptor.html website, What is more important are the pins Ground, SS, SCLK, MOSI, MISO and +5V

Here is what Paul Stoffregen replied to me in an e-mail

peter wrote:

>

> I just put in 2 orders one for a teensy++ and the other teensy, micro

> sd card adapter and 20 pins

>

>

>

> My question is can I solder the card like the one in your picture?

> http://www.pjrc.com/store/sd_adaptor.html

>

Sure. That's all I did, right before taking that picture!

> And second is it possible to do the same on the teensy++ it looks like

> the outputs are differently numbered on the ++ version.

>

Yes, but not so easily. The MISO, MOSI, SCK and SS pins need to line up. If you orient the card the other way and shift it down a few pins, those 4 line up on the Teensy++. However, you would need to run 2 wires for the power. I know that works, because I wired one up that way.

Link to post
Share on other sites
Hi Grayson5.

I have also ordered the micro sd card adapter for the teensy. and am planning on soldering to the teensy 2.0

not the ++ model. because It is easier to do on the teensy 2.0.

disregard the schematics on the http://www.pjrc.com/teensy/sd_adaptor.html website, What is more important are the pins Ground, SS, SCLK, MOSI, MISO and +5V

Here is what Paul Stoffregen replied to me in an e-mail

peter wrote:

>

> I just put in 2 orders one for a teensy++ and the other teensy, micro

> sd card adapter and 20 pins

>

>

>

> My question is can I solder the card like the one in your picture?

> http://www.pjrc.com/store/sd_adaptor.html

>

Sure. That's all I did, right before taking that picture!

> And second is it possible to do the same on the teensy++ it looks like

> the outputs are differently numbered on the ++ version.

>

Yes, but not so easily. The MISO, MOSI, SCK and SS pins need to line up. If you orient the card the other way and shift it down a few pins, those 4 line up on the Teensy++. However, you would need to run 2 wires for the power. I know that works, because I wired one up that way.

Thanks! Any recommendation on which type of soldering iron to get? I have an old one back from the days when I soldered a mod chip on my original XBox, but that tip seems too big.

Link to post
Share on other sites
Thanks! Any recommendation on which type of soldering iron to get? I have an old one back from the days when I soldered a mod chip on my original XBox, but that tip seems too big.

Im not an expert on soldering I just bought an OK one from radio shack.

but maybe you can buy a new tip for yours one thats a bit smaller/pointier

I know when dealing with microcircuits you'll want to keep the heat to a minimum not sure what that is

I just keep increasing until It melts solder. Probably a good idea to search what temp you should run at for microcircuits. and be careful not to heat up an area for too long.

I think the hard part will be trying to keep the card straight on the teensy and not too wonky.

Link to post
Share on other sites

Soldering irons come in 3 fundamentally different types, depending on how they regulate temperature.

The cheapest irons don't regulate at all, other than having limited power that's always on. Often they are specified by their heater's power level, like 20 watts. They heat up slowly and the eventual temperature is only whatever equilibrium is reached with the room's temperature and air flow. Usually they get too hot, and as you solder they get too cold, until they slowly heat back up again.

Better irons switch the heater on and off using a sensor mounted in the iron, usually close to where the tip attaches. Many are electronic and there's an dial or buttons to adjust the temperature. Some have a magnetic switch, where the tip usually has a 6, 7 or 8 stamped on the bottom (for 600, 700 or 800 degrees F) based on how its magnetic properties change. That may seem primitive compared to an electronic sensor, but it actually works quite well since the metal of the tip is more directly involved in the sensing, causing the heater to turn back on sooner as it cools when you apply room temperature solder. Regulated irons usually have powerful heaters, like 40 to 60 watts or more, so they heat up faster and recover faster as you're soldering, but never overheat.

The best and most expensive irons have complex tips with a thermocouple right inside the tip (making the tips also quite expensive).

Unless you have the most expensive type, it's advantageous to use the largest tip that will work for your job. The larger tips simply hold more heat because they physically have more metal, so as you apply the solder the temperature stays more stable. A tiny tip might seem to enable you to work with more precision, but it's a net loss because you won't have a stable temperature. The key to soldering tiny parts is magnification and bright lighting!

When soldering, the MOST IMPORTANT point is to fully heat both surfaces and the solder to a uniform temperature. The ABSOLUTE WORST MISTAKE, which is very common with hobbyists, is quickly touching both the iron and solder to the joint and then withdrawing them both at the same instant. Always withdraw the solder first. You should always leave the iron in contact for another 1/2 to 1 second. That extra second is critical. When the solder is still being applied, part of what will become the final joint is too cold. It has solid, not-melted solder in contact, so it can't possibly be at the correct temperature. That extra second allows all the solder and both surfaces to fully heat to whatever temperature the iron achieves, which hopefully is still hot enough after losing so much just to melt the solder.

If you use the largest tip (lowest temperature loss while soldering) that can do the job and you make sure to spend that extra second after withdrawing the solder, you'll usually see very good solder joints. If you're using a low power, under $10 cheap Radio Shack iron, allow a little time for it to heat back up between each soldering. It's a painfully slow process, but still a lot less painful than trying to debug electronics with flakey solder joints.

The other thing that matters greatly, if you have enough heat and get all the metals up to the same uniform temperature, is clean solderable metals. Pretty much all electronic parts are tin plated for best soldering, but bare copper (eg, many wires) will corrode rapidly. The flux is a chemical that's inside the solder. Afterwards, you'll notice the residue on the board. It cleans the corrosion from the metal while you're soldering. If your metals aren't perfectly (and we live on a planet with lots of oxygen which pretty much assures there will be some corrosion), you absolutely must have flux... and there isn't much inside the solder.

To make best use of the flux, you must apply the iron to the area, and then apply the solder. As the solder melts, the flux will spill all over the nearby area. The smoke you see is the flux burning, which is BAD. You don't want to waste the flux into smoke. The WORST thing you can do is apply the solder to the iron and watch the smoke roll off while all the flux burns away, and then try to touch the metal surfaces with the melted solder. There won't be any flux left. The solder will barely "stick", because even if the metal looked clean there's a microscopic layer of corrosion between the metal and your solder. You want to make best use of the flux to clean away that corrosion, which means touching the solder to that area so as it melts the flux will spill all over and clean the 2 metal surfaces you're trying to join.

You can get flux separately, usually in liquid form. Often it's sold in a "pen" which dispenses a tiny amount. More flux will help greatly on difficult soldering. It's best to get the same type of flux as is in your solder, if you can.

Beware of water soluble flux, like the Kester 300 series. It works extremely well, but you MUST wash the finished product with water to remove it. It's highly corrosive and will destroy your work it left on long term. An hour is no big deal, so there no urgent rush to get to the sink. After washing, for many types of soldering it's necessary to bake the entire product to remove water than lingers in tiny crevices. 10 minutes in an oven at 150 to 170 F works pretty well.

Rosin fluxes can be left on the board. Kester 44 (60-40 lead based solder) is generally the easiest and best for prototyping.

One last thing I should mention is the concern about too much heat. Certainly there is a point where too much will cause damage. However, it's a LOT more than you might think. Long ago, like in the 60s and 70s, when some transistors and diodes were made from germanium instead of silicon, heat from soldering could destroy the parts. It was common to clip a heatsink on component leads, and there's still lingering lore about this ancient practice which hasn't been necessary for decades!

How much heat is too much can be hard to judge. The biggest concern with manual soldering is physical damage, especially if the parts can move while you're working. The heat can weaken the bond between copper and fiberglass on a circuit board, or melt the plastic insulation on wire (unless you're using the spendy Teflon insulated wire, which is awesome stuff for prototyping). Taking measures to prevent movement of either surface really helps.

Pretty much all modern parts can withstand 30 seconds of soldering, though the temperatures guaranteed are pretty low. You can't work as such low temperatures with cheap soldering irons, even with a giant tip, because the temperature just isn't stable when you apply solid solder and drain way heat to melt it.

Most manufacturing processes bake the entire circuit board for several minutes at a temperature slightly below the melting point of the solder, and then heat the entire board above melting for 20 to 30 seconds. The key point to remember is they subject everything to elevated temperature, not quite enough to melt the solder, for a VERY LONG TIME, at least a few minutes. All modern parts are designed for this.

If you have a regulated iron, it's best to set for 600 degrees F and use the largest tip you can. Get everything heated to a uniform temperature, allowing an extra second, and make best use of the flux, and focus any concern about overheating to keeping the parts still while you're working. If you follow this advise above, you'll get very good results.

Edited by Paul Stoffregen
Link to post
Share on other sites
  • 2 weeks later...
Wow, Paul. Thanks very much for the details on soldering. I plan on attacking the project tonight when I get back into town.

OK, need a little help/advice here with the SD card. I've soldered the pins onto the SD chip so I could use it with the breadboard. I then tried to connect it to the teensy using wires (see the two pictures - attachments). 5 wires on each side of the SD card connecting it to the first five pins of each side of the teensy chip.

My question is: should my PC see the SD card when I plug the teensy into it? I was expected an F: drive or something to show up?

The code on the board is currently just some test code to open CMD and do a directory listing. I've not compiled the SD library yet since I wanted to first make sure the PC could see the SD card.

Is this a valid approach? Am I doing something wrong/incorrect here?

Thanks for any help.

post-20751-1282403529_thumb.jpg

post-20751-1282403540_thumb.jpg

Link to post
Share on other sites

Update: I was able to get the Teensyduino 0.9 and Teensy Loader 1.06 to work and compile the Blink code.

Now when I plug the teensy into the PC the PC registers an E: drive but I cannot access it. It says "Please insert a disk into removable drive E:". I have a 2GB Sandisk card in the SD drive. I know this card works since I use it in my Blackberry.

Any suggestions?

Link to post
Share on other sites
Update: I was able to get the Teensyduino 0.9 and Teensy Loader 1.06 to work and compile the Blink code.

Now when I plug the teensy into the PC the PC registers an E: drive but I cannot access it. It says "Please insert a disk into removable drive E:". I have a 2GB Sandisk card in the SD drive. I know this card works since I use it in my Blackberry.

Any suggestions?

I'm not sure where I got this link from, maybe on these forums?

but was told that sd cards should be formated in a particular way

http://panasonic.jp/support/global/cs/sd/download/index.html

I hope this helps because I have yet to test my sd card reader.

also search the forums because apparently the brand and model of card can make a difference.

Link to post
Share on other sites
apparently the brand and model of card can make a difference.

I wrote the Teensyduino code to (hopefully) work with any SD card.

If you find one that does not work, but others do (eg, your hardware is confirmed working with other cards), please contact me directly at paul at pjrc dot com and I will swap a known-to-work card of similar or better specs for yours... and of course I'll (eventually) use your card for testing compatibility of future releases. My current collection spans 16 megs to 4 gigs, both version 1 and 2 cards, and both SD and SDHC in version 2. Teensyduino has been tested with all those cards.

Link to post
Share on other sites

Paul,

I'm not sure what the issue is. I have both an SanDisk and PNY microSD card (both 2GB). They both work with the microSD adapter, but when I try to read the card with my Teensy and SD card adapter I get a "Please insert disk" error.

Any idea what this could be? I soldered the pins onto the SD card and I am using a breadboard to connect the SD card to the Teensy per the pictures in my post above.

Any help/suggestions would be appreciated.

Thanks!

Edited by Grayson5
Link to post
Share on other sites
Any idea what this could be?

Very likely a loose or unconnected wire.

First, only 6 pins are needed: +5, gnd, miso, mosi, sclk, ss. So rip out those other 4 wires that do nothing, assuming you're working on that breadboard.

Grab a voltmeter. Set it to a range that can measure 5 volts DC (eg, if there's 2, 20, 200, you'd use 20). Use a clip lead to attach the black wire to the USB metal shell, which is ground.

First, measure the voltage on +5 and gnd at the SD adaptor. Try to touch the side of the solder joint close to the actual pad on the PCB, not the pin in the center. +5 should measure about +5 volts. A little lower is fine, many PCs run about 4.8, and if you're using a hub it can be as low as 4.4. Anything over 4 volts is probably fine, but do also measure over on the Teensy and make sure they are the same.

Measure the ground pin too. This probably sounds redundant, but if ground isn't connected nothing will work. Observe how your meter responds with the red wire in your hand. You can touch it if necessary to get something to happen. When you touch the ground pin, you are looking for a "solid zero", which should look distinctly different from the zero that fluctuates a bit on its own or when you touch the wire.

Repeat for the signals. For MISO, you should see 3.3 volts when there's no activity to the card, or no card inserted.

For the other 3, use the blink example, but change the pin number to the signal you want to test. Adjust the times if your meter responds slowly. Measure the voltage on the actual pin and watch for it to "blink". Measure the other voltages and make sure they do not "blink".

Again, it's helpful to measure on the Teensy side and on the SD side. Since they're connected by a wire, they should be identical. You'll probably find one that isn't.

Link to post
Share on other sites

Thanks Paul. I will pick up a voltmeter tomorrow and follow your instructions.

One other strange thing is happening. When I unplug the SD card from the breadboard and just plug in the teensy I still get the same error. The PC thinks that there is an "E" drive when the SD card is not even plugged in.

I am using Arduino-0018 and teensyduino 0.9 and I imported the SDfat library (although I am having problems compiling the examples. I get the following errors

from C:\John\Security\arduino-0018\libraries\SdFat\SdFile.cpp:22:

c:/john/security/arduino-0018/hardware/tools/avr/lib/gcc/../../avr/include/math.h:439: error: expected unqualified-id before 'double'

c:/john/security/arduino-0018/hardware/tools/avr/lib/gcc/../../avr/include/math.h:439: error: expected `)' before 'double'

c:/john/security/arduino-0018/hardware/tools/avr/lib/gcc/../../avr/include/math.h:439: error: expected `)' before 'double'

I will continue to try and get this to work... :)

Link to post
Share on other sites
When I unplug the SD card from the breadboard and just plug in the teensy I still get the same error. The PC thinks that there is an "E" drive when the SD card is not even plugged in.

That's what it should do, exactly the same as a USB card reader when there's no media present.

Link to post
Share on other sites

Yes! Got the SD card to work. Following Paul's suggestion I got a voltmeter and could see that the SD card was not getting power. I re-soldered that pin and now the PC can read the card.

Thanks for the help Paul. Now on to the fun stuff.....coding!

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...