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EEPROM Questions — Parallax Forums

EEPROM Questions

HMSTLHMSTL Posts: 16
edited 2010-11-29 20:20 in Propeller 1
Hello, sorry but I am trying to understand EEPROM.

It seems people store their code on it but I was wondering why not use the Propeller's ROM? Unless I am misunderstanding something (which I must be), it has the same amount of ROM as the I2C EEPROM in the parallax shop.

Comments

  • W9GFOW9GFO Posts: 4,010
    edited 2010-11-29 19:16
    This is an easy one to answer. ROM stands for Read Only Memory. Since you cannot write to it, you cannot put your program onto it.

    The data stored on the Propeller's ROM is put there during manufacturing. It cannot be changed.

    EEPROM stands for Electrically Erasable Programable Read Only Memory. It can be read from an unlimited number of times but writing to it slowly wears it out. It can be written to many tens of thousands of times.


    Rich H
  • HMSTLHMSTL Posts: 16
    edited 2010-11-29 19:24
    Ohh... Thank you.

    All the chips I've programmed have had EEPROM built-in. I didn't understand the difference, but I do now, thanks to you.

    So let's say I was making a product with a PCB using Propeller and EEPROM and wanted to put my code on it. To do this could I have the completed board made with everything soldered but the EEPROM and then use a completely separate development board just for the sake of putting the program on the EEPROM, and then just move the EEPROM to the end-product PCB?

    Thanks again.
  • HarleyHarley Posts: 997
    edited 2010-11-29 19:33
    HMSTL,

    You'll be happy to know that the EEPROM can be socketed and maybe never have to be removed, as it is programmed in place. For minimal components on a board, use a Prop Plug for programming and USB interfacing.

    EEPROMs require different cells than the other logic on silicon. The process for the Prop I doesn't support internal EEPROM cells.

    Ohh... Thank you.

    All the chips I've programmed have had EEPROM built-in. I didn't understand the difference, but I do now, thanks to you.

    So let's say I was making a product with a PCB using Propeller and EEPROM and wanted to put my code on it. To do this could I have the completed board made with everything soldered but the EEPROM and then use a completely separate development board just for the sake of putting the program on the EEPROM, and then just move the EEPROM to the end-product PCB?

    Thanks again.
  • W9GFOW9GFO Posts: 4,010
    edited 2010-11-29 20:10
    HMSTL wrote: »
    To do this could I have the completed board made with everything soldered but the EEPROM and then use a completely separate development board just for the sake of putting the program on the EEPROM, and then just move the EEPROM to the end-product PCB?

    You could do it that way but it might be easier to design your board with four pads to be used only for programing the EEPROM in place using a Prop Plug or Prop Clip, like Harley said.

    Rich H
  • HMSTLHMSTL Posts: 16
    edited 2010-11-29 20:20
    Thank you for explaining this to me, but my goal is to make as compact a PCB as possible. That said, there will probably be room on one side to add those pads. Not sure how to do that, though...
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