I think I understand how one can use an Arduino to program an external EEPROM memory chip. I am wondering if there are any memory chips that don't need any type of micro controller to operate. So, for example, some chip where the address/location in the memory is controlled only by setting high and low on certain pins. Are there, for example, any 256 bit chips that has 8 pins for the address and maybe 8 others for the data? I would mostly be interested in non-volatile memory.

I am not trying to do anything. I am just curious.

  • 1
    \$\begingroup\$ To program an EEPROM you need to apply certain signals to it in a certain order. A microcontroller makes this easy, you just make a program that makes this sequence. That does not mean you cannot do the same with for example a set of switches to switch the EEPROMs inputs between 0 and 1. That does not sound very practical to me but for sure it can be done. Maybe not on all EEPROMs but on some simple ones for sure it would work. \$\endgroup\$ May 12, 2016 at 19:54
  • \$\begingroup\$ @FakeMoustache: Ah.. so you don't actually need a micro controller? Does speed matter when you do this? (I am really only curious and not interested much in the practical parts.) \$\endgroup\$
    – John Doe
    May 12, 2016 at 19:56
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    \$\begingroup\$ See How to program an EPROM by hand! \$\endgroup\$
    – Transistor
    May 12, 2016 at 20:00
  • \$\begingroup\$ Note that this is a followup to a question asked in Arduino.SE \$\endgroup\$
    – Dave Tweed
    May 12, 2016 at 20:04
  • \$\begingroup\$ It depends on the EEPROM if speed matters, see the datasheet to find out. That's why I wrote that it might not work on all EEPROMs. \$\endgroup\$ May 12, 2016 at 20:12

1 Answer 1


What you are describing is parallel access memory. Most memory was like that back years ago. When memory was small, bringing out all the address and data lines separately was at least feasible. A common static RAM back in the 1970s was 1 kBits organized as individual bits. It therefore had 10 address lines, one data line, and a few lines that caused reading and writing to happen.

Today, such a memory would be absurd due to the large number of pins it would require. For high speed systems, memories are still parallel access, but the pins are usually multiplexed. For example, there may only be half the number of address pins as address bits, and it takes two cycles to read in a arbitrary address. Most accesses are sequential, and the controllers are smart enough to only write the upper bits when they need to be changed.

Micocontrollers don't need the speed of large systems with large memories, but their pins are limited, so serial makes more sense. Of course now significant memory is built into microcontrollers, which is even simpler to access than a external chip.

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    \$\begingroup\$ Note that you can still find some parallel EEPROM. Although it seems mostly legacy stuff. \$\endgroup\$
    – dim
    May 12, 2016 at 20:31

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