Featured Articles
Announcing Pi
Technical Specifications
Raspberry Pi FAQs
Win a Pi
Raspberry Pi Wishlist
Actions
Forum Thread Details
  • Replies 188 replies
  • Subscribers 717 subscribers
  • Views 22799 views
  • Users 0 members are here
Related

Raspberry Pi - Hardware Flaws and Fixups?

e14 Contributor

Several people have commented on the hardware design of the Raspberry Pi.  Some are buried in other topics so please post your comments here.  I'll try my best to answer questions about the design decisions we made.  The Raspberry Pi is not perfect, never will be.  I've always found that perfect designs have a habit of never getting built, engineers are always a bit guilty of that, but I had Eben phoning/emailing me every day wanting to know when it would be finished.  Also, one persons perfection is another persons nightmare.

 

e14 is the home for engineers so please contribute to make Raspberry Pi better.

 

Thanks

 

Pete

Parents

  • Would it be possible to connect the data pins of the power microusb so that a data cable may be used to connect the pi to a desktop computer (software permitting)? Would this need a more advanced USB hub and therefore be more expensive?  It could be very useful in the educational environment where a student needs to power the device and also transfer files between the schools network and the device

Reply

  • Would it be possible to connect the data pins of the power microusb so that a data cable may be used to connect the pi to a desktop computer (software permitting)? Would this need a more advanced USB hub and therefore be more expensive?  It could be very useful in the educational environment where a student needs to power the device and also transfer files between the schools network and the device

Children
  • in reply to ld0614

    Yes, that'd be a nice feature....

     

    However it's not as simple as simply connecting a few wires.

     

    The SOC apparently has  USB-host circuitery. I don't think it has an USB-device module. So there simply isn't anything to connect those datalines to. :-(

     

    Possibly the USB module is capable of doing both device and host. However there is just one USB connection. So you have to chose where to connect it. It has been connected to the USB hub/lan chip, so now the flexibility is lost.

     

    Hans, the lan 9513 is 64 pins and therefore physically a lot bigger. Probably more expensive too.

  • in reply to rew

    Hi Roger, long time no see... Still living in Delft and doing I2C kernel activities... ?

     

    What I see from the docs at smsc  the lan9512/13/14 are all Compact 9x9mm, RoHS-compliant, 64-pin QFN package

    price difference what I can find is 0.30 - 0.40  between an lan9512 and lan9514

    It is only an option if they are thinking about a redesign of the pcb... (probably not). since you also need space for a connector..

     



  • in reply to e14 Contributor

    Hi Hans, Yes still living in Delft. Yes I'm working on I2C / SPI right now, but have I done that before? Hmm.

     

    Anway, looking at the chip on my RPI, I noticed that it had 64 pins instead of the 48 I was expecting. I apparently misread the datasheet. Happens every now and then. :-(

     

    Re: SD cards:  I have a 4G kingston card, which apparently locks up every now and then. Things stop for 5 seconds and then get going again (the kernel prints something about a timeout).

    I'm hoping that the fix by Russel King for this works.

     

    Pete,

    R34, the current limiting resistor for the power Led, is too small. It hurts my eyes. In the old days you'd use something like 220 or 330 ohms. Nowadays you'd take say 1k. (which it probably is). I decided to go for 10k on one of my designs, but didn't realize that there were 15k resistors in my storage box labeled 10k (which is short for 10-20k), So I soldered on 15k, and I like that....

     

    Pete, are these resistors 0402 or 0603? I'll measure when I get a chance. Maybe I'll swap it out one day if it irritates me enough.... But most likely not before I can manage to have a spare RPI on hand.

     

    The one on the yellow led has the same problem, but not as dramatic. 2k2 or 3k3 would do if it is now 1k.