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New Propeller Platform SD Module - What should go on it? — Parallax Forums

New Propeller Platform SD Module - What should go on it?

Nick McClickNick McClick Posts: 1,003
edited 2010-03-15 05:35 in Propeller 1
I've been cooking up a new Platform Module - this is the Propeller Platform SD. First the basics;
  • 2.8" x 2.5"
  • Compatible with all other Platform Modules (DMX IO, LCD UI, ProtoPlus, El Jugador, OctoDriver, PropNet, Prototyper, Tester, Battery, etc).
  • Will come 100% pre-assembled and tested.
  • Includes 512kb EEPROM, 5Mhz socketed crystal, and uSD card slot
  • Super low dropout regulators- although I put 7V on the pcb, they'll run within 100mV of the output voltage, so 5.1v input minimum.
  • Comes with a special bootloader so you will be able to program a Prop without a Programming stick!
I've attached a picture of a prototype I've been testing for the past few weeks. I put it together by hand so it's a little grungy, but the final versions will go to an assembler (You can see the fiducials in the photo).

The part I'm most excited about is actually the software - the Prop Platform SD will come with a special bootloader so you can program without a PropPlug. This way, you can update your program in the field, without a computer. You can also easily switch programs by swapping memory cards. Programming with a PropPlug / Clip is still an option and headers are on the board. Once your program is running, it can access the SD card like normal, so it's great for doing stuff like datalogging, menus, etc.

Feedback
I've been testing it for a while, and there are enough 'little things' that I want to change, I've decided to re-rev the design. I thought I'd ask for feedback to see what else should be changed / added / removed.

Also, a few specific questions:
  • Does anyone use a USB2SER adapter? The Propeller Platform has connections for it, not sure if I should keep it on.
  • The bootloader will work by looking for files on the uSD card. If there's a 'run.bin' on the uSD, the Prop will start executing it. If there's a load.bin, it will load that file into the upper half of the EEPROM. If nothing is found, it will load the upper half of the eeprom. If there's a load.bin AND a run.bin on the uSD card, which should the bootloader update the EEPROM or execute run.bin?

For Rev. B, I was going to fix the uSD jumpers, add more vias under the vregs, change the silkscreen to reflect min. voltage of 5.5v, and use a different uSD slot (everyone has problems assembling the 3M slot). Any other suggestions for a re-rev? Would a Propeller Platform with a built-in SD card reader and bootloader be useful?

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Comments

  • RsadeikaRsadeika Posts: 3,824
    edited 2010-03-04 19:05
    Before I make any suggestions, I would like to know what will be the price tag for what you have shown? The board looks neat and uncluttered, so I do not think that you have all that much room to put anything else on it. I also like the idea that it will be assembled, maybe in China, to get a real good price for the consumer. So, what would be a guess as to the cost.

    Ray
  • Nick McClickNick McClick Posts: 1,003
    edited 2010-03-04 19:18
    My goal is between $30 and $40. I'm hoping this is a cool board for advanced users, but I especially want to make it appealing to beginners.

    If a beginner asked you, "What should I buy to get started with the Propeller?", what would prevent you from recommending the Propeller Platform SD?

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  • RaymanRayman Posts: 13,901
    edited 2010-03-04 19:43
    Looks good. Is the power jack going to get in the way of shields?

    Personally, I put a ceramic cap on all 4 sides of the Prop, but that's probably overkill (usually).

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  • hover1hover1 Posts: 1,929
    edited 2010-03-04 19:53
    Nick,

    Nice board. Not sure what Ray meant, but there is plenty of real estate left on the board, it is double sided, right?

    I can't think of any add-ons right at the moment. Others might say you need more caps around the Prop chip.

    I would keep the PropPlug connector. What happens if you over write the bootloader by mistake with a renegade program? You will need some way to get it back on, or am I missing something?

    As always, you keep coming up with great products to service the Propeller community. Much success with this one!

    Jim

    PS You have to change one of the green LED's to blue. You can't have a board nowadays that doesn't have a blue LED! Think RGB.
  • pullmollpullmoll Posts: 817
    edited 2010-03-04 19:59
    This looks interesting to me, since designing and coding up a data logger is exactly why I started looking at the Propeller chip. If your board is suitable for my purposes, I'd be interested. The price range you gave is well in the range that I, or rather my contractor, would invest. I just would have to code up the logging and have a setup SD, and in a running system could then use a data SD to fill it with log data. This is almost exactly what I need smile.gif

    Juergen

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    Next day he was buried. Face down, nine edge first.

    Post Edited (pullmoll) : 3/4/2010 8:04:07 PM GMT
  • RsadeikaRsadeika Posts: 3,824
    edited 2010-03-04 20:17
    Since you will be targeting beginners, maybe a USB connection would be a better choice as opposed to the prop/clip plug. I do not know how that would affect the price tag though. As for the "real estate" comment on my part, not having designed any boards, it looks to me, like it would not fit anything else. I would like to see, along side the barrel receptor, a screw connector for an external battery source. It is easier to take two wires from a 12V battery, and screw them down, instead of trying to solder up a barrel plug.


    Ray
  • hover1hover1 Posts: 1,929
    edited 2010-03-04 20:36
    Ray,

    Assuming it is a double sided board, (traces on top and bottom), many of the traces on the top could be rerouted to the bottom layer leaving some room on the top layer for other connectors. Given that all the I/O lines are brought out to the header·this is probably a non isssue. The number of vias might affect the board cost though.

    A USB connection would add more cost in parts and assembley, Nick would have to say how much based on the·numbers he is going to produce.

    A 2 position screw terminal is a good idea, and looks like it could be added in parallel with the barrel connector.

    Jim
    Rsadeika said...
    Since you will be targeting beginners, maybe a USB connection would be a better choice as opposed to the prop/clip plug. I do not know how that would affect the price tag though. As for the "real estate" comment on my part, not having designed any boards, it looks to me, like it would not fit anything else. I would like to see, along side the barrel receptor, a screw connector for an external battery source. It is easier to take two wires from a 12V battery, and screw them down, instead of trying to solder up a barrel plug.


    Ray
  • JonnyMacJonnyMac Posts: 8,929
    edited 2010-03-04 20:41
    Nick,

    I'd love to see an DS1307 on the I2C buss (you'll need a pull-up on the SCL pin as well) and a small, coin-cell battery holder.

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  • Nick McClickNick McClick Posts: 1,003
    edited 2010-03-04 21:08
    Agreed on the Screw Terminal - I forgot about adding that, but I originally wanted to.

    I might be the crazy one on this, but I don't want to add USB because of (1)Cost: The FTDI alone is about $3, and (2) Use: I believe an SD card is more useful in most projects. It's a bit of a compromise, you get a cheaper board that is more useful, but it's less convenient for doing development. You can still compile a binary and copy to an SD card, though.

    I believe most beginners just want to test the waters, and they're looking for a cheap way to do so. Once they're hooked, they'll likely pick up a Prop Plug, anyway.

    There isn't much real estate unless I want to do double-sided SMT assembly, which would blow out the cost. I do have caps on each pair of Vdd pins (a .47 ceramic, a 47uf Al next to everything and a 4.7 Tantalum), this is more than the USB protoboard, so I have to assume I'm okay there.

    @Juergen - I'll pre-program with a bootloader, but it's easy to re-program with your own software. Essentially, you've got a Propeller with SD, 512k eeprom and 1.5a 5v and 3.3v

    @ray - I use nifty .318" pin headers, so there's clearance. Here it is with an Octodriver.

    @Jon - So would I, but I think it will push up the price too much. Maybe I can at least add pads so that someone can add it if they want to.

    Anyone use USB2SER?

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  • jazzedjazzed Posts: 11,803
    edited 2010-03-04 21:16
    I agree on not having USB on board. I have some boards with FTDI USB and am a little annoyed that my port enumeration is now up to COM20. USB2SER is cheaper I guess and the PropProto board has pin-out for it, but as I remember that is a 5V device which may be a problem for some folks.
  • hover1hover1 Posts: 1,929
    edited 2010-03-04 21:25
    Jon, excellent suggestion!

    I was going to suggest a couple of SOIC-8 pads on the board, like the SX-48 board, but then there needs to be jumpers so the lines don't go to the outside world ,(headers).

    But I guess that could be just a couple of pads that get soldered, or not. Should not add any cost to the board, but a little bit more documentation.

    Jim


    JonnyMac said...
    Nick,

    I'd love to see an DS1307 on the I2C buss (you'll need a pull-up on the SCL pin as well) and a small, coin-cell battery holder.

  • rokickirokicki Posts: 1,000
    edited 2010-03-04 21:26
    I'd say you really want either a propplug/propclip connector, or USB onboard. Anything else is too unwieldy.
    For price reasons, propplug/clip is plenty; no need for FTDI onboard.

    And if possible, it should be optionally powered from the propplug (is this even possible?).

    But this looks *extremely* sweet. If this hits the lowest-price, SD+prop solution out there, expect to sell
    a whole pile of them. I'd by several right off the bat.

    The software is cool, no doubt, but getting this out soon and cheap would be all sorts of excellent.
  • John AbshierJohn Abshier Posts: 1,116
    edited 2010-03-04 21:40
    I have USB2SER for use on a board that uses that instead of PropPlug. I don't think you need to add connectors for USB2SER. As for as I know it is an obsolete part. Please put a pull up on both of the I2C lines. That makes it easier to use I2C devices. load and run: I would pick run over load; run seems more immediate. Pick one and document it. Another option would be to copy load.bin and run run.bin. I would pick screw terminals or a a polarized header (like on the Robot Control Board) over the barrel plug for power. Please do not install the two rows of female headers. Users may want to use male or point to point wiring. Overall It looks like a very nice board and I will buy a couple.

    John Abshier
  • rokickirokicki Posts: 1,000
    edited 2010-03-04 21:43
    I sort of like the female headers; this lets me use the board for breadboarding without any additional work.

    I also like the barrel jack; it's standard across prop boards (demo board, proto board, etc.) and lets me use
    the same power supplies across all my prop projects.
  • MagIO2MagIO2 Posts: 2,243
    edited 2010-03-04 21:50
    In general I like that board - as I do the old one ;o)

    But I'd prefere to have the FTDI chip on it. Especially beginners will change programs in little steps. So, if they safe the money for a PropPlug they'd have to swap the SD card very frequently. If you have the FTDI chip on board you can download the programs to the SD card using XMODEM.

    Maybe to keep the additional price for that a bit lower you can get rid of the 5V part. There are 5V power plugs available for little dollars. So if someone needs the 5V he can use such a power plug. This solution will still be compatible with your modules.

    For the bootloader .. I think I'd suggest to program the EEPROM with load.bin AND run the run.bin from SD card in this case. This way someone can use the load.bin to put data or maybe PASM drivers to the upper 32k.
  • Nick McClickNick McClick Posts: 1,003
    edited 2010-03-04 21:52
    Remember, too, that the system is designed to be modular, so you'd do most of your prototyping / circuit on another module or on a breadboard.

    @rokicki - there's a PropPlug / Clip connector onboard. The SD slot is meant as a nice feature for advanced users or a way to get started without buying a Prop Plug if you're a beginner.

    @John A - for bootloader, that's what I was thinking, too. The default option should be less destructive. I really like saying '100% pre-assembled', but you're right, it might be more flexible to include a barrel jack and screw terminal but not solder it on. Same deal with the pin sockets. The vregs are pretty nice, so it seems like a waste to lock them down to a barrel jack.

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  • ElectricAyeElectricAye Posts: 4,561
    edited 2010-03-04 22:00
    JonnyMac said...
    Nick,

    I'd love to see an DS1307 on the I2C buss (you'll need a pull-up on the SCL pin as well) and a small, coin-cell battery holder.

    A Real Time Clock makes a lot of sense to me, too. What's data logging without a time and date?

    smile.gif
  • John AbshierJohn Abshier Posts: 1,116
    edited 2010-03-04 22:05
    Perhaps you shoud offer two options:
    1. Fully assembled. Barel jack for a wall wart, female headers to use jumper wires to a breadboard.
    2. Partially assembled. Power IO and headers not installed. My problems with barrel jacks are that most batteries don't have a plug and the plug sticks out over an inch (1 1/4 inches on the robot I am working on presently).

    John Abshier

    P.S.· Reference decoupling caps.· How about testing it out with the 6.25 MHz crystal.· I wouldn't sell it with a 6.25 MHz crystal since most software, especially that oriented to beginners, is coded for a 5 MHz crystal.

    Post Edited (John Abshier) : 3/4/2010 10:11:04 PM GMT
  • Al BoothAl Booth Posts: 137
    edited 2010-03-04 22:18
    The new design looks really good. And I like the addition of the bootloader and the SD socket. And the expected price.

    I have 2 minor concerns:
    1 - I would like to see the Plug/Clip holes away from the edge so that the right angle header pins are protected by the card edge, as in the original Platform.
    2 - The new card is connector compatible with the old Platform, but not mounting hole compatible. It is about 1 inch shorter and only 2 of the 4 mounting holes line up. I use stand-off between the cards to make the stack more secure. And so far I only use the platform, prototyper, and LCD UI for that reason.

    For the beginner, perhaps you could do a ProtoPlusPlus that adds the solderless breadboard option and adds LED's and such to match the PE Labs examples.
  • Brian RileyBrian Riley Posts: 626
    edited 2010-03-04 22:44
    I like this board!

    1 - lose the USB2SER position. Its obsolete and the only board I know of thats still used by anyone thta is tied to a USB2SER is my Wulfden version 1.02 PRC (circa 2006) . If they are still active and have no other solutions I will personally give them a 'tweenie' board that alters the USB2SER pinout to match the Prop Plug.

    2 - while we are on that subject, I would ask for one more hole/pin (5th position) to the 4 pins for the PPlug/PClip. The fifth pin would have 3.3v and make it easier for anyone who has hand built an RS232 transistor interface and which, oh by the way ;=), would fit my Wulfden P1 version of said interface directly.

    3 - I concur with suggestion to put both pullups on I2C

    4 - there's room, why not a second EEPROM like the original platform?

    5 - I whole-heartedly second John's suggestion about offering a version with connectors included but not installed.

    figure on two or three of these at least from me .... nice work

    cheers ... BBR

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  • Nick McClickNick McClick Posts: 1,003
    edited 2010-03-04 23:40
    USB2Ser is lost. I've added a second set of pins behind the PropClip for a R/A header for a PropPlug, too.

    I'll add the second pull up, too.

    Some modules are 3.8x2.5 (LCD UI, DMX IO, Prototyper, Propnet, Tester), and some are 2.8x2.5 (protoplus, El Jugador, TermBoard, Battery, OctoDriver), this board lines up with the small module size. I was thinking of doing a combo protoplus + SD with mini-breadboard, but I didn't think of including discretes - that's a good idea.

    I'll try to fit in space for a second EEPROM and RTC. They would be optional (to keep the price down), but I'll see if I can at least fit the pads.

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  • Rob7Rob7 Posts: 275
    edited 2010-03-05 00:34
    Hi Nick,
    Great board, I like it.
    I don't think that the USB2SER is "Obsolete".
    I think you will find that many Home Brewed Propeller users are still out there.
    I do have one Propeller board, My first and most reliable proto board and it "uses it".
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  • tonyp12tonyp12 Posts: 1,950
    edited 2010-03-05 00:43
    How about a·HID USB loader?, skip the cost of FTDI chip.

    It's slow, but BradC says he can make it faster.

    http://forums.parallax.com/showthread.php?p=675656

    With a SD and HID Loader in eprom, maybe need to make it write protected?
    ·
  • ForrestForrest Posts: 1,341
    edited 2010-03-05 01:11
    Great board. I also would like to see the pads for the DS1307 (thru hole please) and don't forget holes for the watch crystal.
  • Bill HenningBill Henning Posts: 6,445
    edited 2010-03-05 01:50
    Nice board!

    I'd add the other pullup on I2C, and a +3.3V 5th pin for the PropPlug header area... then it would be compatible with SerPlug [noparse]:)[/noparse]
    Nick McClick said...
    I've been cooking up a new Platform Module - this is the Propeller Platform SD. First the basics;
    • 2.8" x 2.5"
    • Compatible with all other Platform Modules (DMX IO, LCD UI, ProtoPlus, El Jugador, OctoDriver, PropNet, Prototyper, Tester, Battery, etc).
    • Will come 100% pre-assembled and tested.
    • Includes 512kb EEPROM, 5Mhz socketed crystal, and uSD card slot
    • Super low dropout regulators- although I put 7V on the pcb, they'll run within 100mV of the output voltage, so 5.1v input minimum.
    • Comes with a special bootloader so you will be able to program a Prop without a Programming stick!
    I've attached a picture of a prototype I've been testing for the past few weeks. I put it together by hand so it's a little grungy, but the final versions will go to an assembler (You can see the fiducials in the photo).

    The part I'm most excited about is actually the software - the Prop Platform SD will come with a special bootloader so you can program without a PropPlug. This way, you can update your program in the field, without a computer. You can also easily switch programs by swapping memory cards. Programming with a PropPlug / Clip is still an option and headers are on the board. Once your program is running, it can access the SD card like normal, so it's great for doing stuff like datalogging, menus, etc.

    Feedback
    I've been testing it for a while, and there are enough 'little things' that I want to change, I've decided to re-rev the design. I thought I'd ask for feedback to see what else should be changed / added / removed.

    Also, a few specific questions:
    • Does anyone use a USB2SER adapter? The Propeller Platform has connections for it, not sure if I should keep it on.
    • The bootloader will work by looking for files on the uSD card. If there's a 'run.bin' on the uSD, the Prop will start executing it. If there's a load.bin, it will load that file into the upper half of the EEPROM. If nothing is found, it will load the upper half of the eeprom. If there's a load.bin AND a run.bin on the uSD card, which should the bootloader update the EEPROM or execute run.bin?

    For Rev. B, I was going to fix the uSD jumpers, add more vias under the vregs, change the silkscreen to reflect min. voltage of 5.5v, and use a different uSD slot (everyone has problems assembling the 3M slot). Any other suggestions for a re-rev? Would a Propeller Platform with a built-in SD card reader and bootloader be useful?
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  • RaymanRayman Posts: 13,901
    edited 2010-03-05 01:51
    If you do add a DS1307 (my favorite RTC), you could consider using an ultracap instead of coin cell for the backup. I think the ultracap is smaller and is just 2 through holes... Haven't tried this myself, but could make sense if space is an issue...

    Or, you could make pads for a coin cell on the bottom layer, which I what I've been doing...

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  • Nick McClickNick McClick Posts: 1,003
    edited 2010-03-05 05:06
    I'll use a super cap - I have extras for the PropNet, too.

    @ bill - what side does the +3.3v go? Next to Vss?

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  • Nick McClickNick McClick Posts: 1,003
    edited 2010-03-09 00:33
    Okay, here's Rev. B;

    I've changed a few things;
    • Added a second pull-up resistor so both SCL and SDA are pulled up.
    • Added space for a DS1307 RTC with xtal and a super Cap (.33F) and a diode (I'm thinking 1n4148) to keep the cap from flowing back into Vdd
    • Removed the V50 and V33 power LED's
    • Added connectors to a prop plug
    • Removed uSD jumpers. You can just hold your soldering iron over the resistor array, though, if you want to remove the pullups on P0..P3

    I've attached the pcb and schematic. Lookin' good?

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  • Brian RileyBrian Riley Posts: 626
    edited 2010-03-09 02:03
    Nick McClick said...
    Okay, here's Rev. B;

    I've changed a few things;
    • Added a second pull-up resistor so both SCL and SDA are pulled up.
    • Added space for a DS1307 RTC with xtal and a super Cap (.33F) and a diode (I'm thinking 1n4148) to keep the cap from flowing back into Vdd
    • Removed the V50 and V33 power LED's
    • Added connectors to a prop plug
    • Removed uSD jumpers. You can just hold your soldering iron over the resistor array, though, if you want to remove the pullups on P0..P3

    I've attached the pcb and schematic. Lookin' good?

    I will ask once again on behalf of myself and Bill Henning ... can you add a hole for a "pin 5" connected to 3.3v on the Prop Plug position to accommodate my P1 and Bill's SerPLug ???

    otherwise ... lookin' awesome

    cheers ... BBR

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  • Nick McClickNick McClick Posts: 1,003
    edited 2010-03-09 02:15
    I'll have to pull 3.3v down to that part of the board, but it should work. Pin 5 means next to the reset switch, right?

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