Can you boot propeller from an EEPROM smaller than 32K?

Dennis Ferron

I have an "orphan" extra propeller chip and I've been having trouble finding a 32K EEPROM for it. What happens if you try to use a smaller EEPROM? Will the Propeller load code from it ok? Will it work with the Propeller tool?

As an extreme example, I even have a 1K EEPROM; I don't expect that to actually work but I am interested in how small you can go.

Peter Jakacki

I guess it is only the 16-bit eeprom addressing that is important, so that means anything from a 24lc32 onwards will do the trick. The smaller devices use just a single byte for the memory address and distribute A8,A9,A10 onto the device address so that makes them unsuitable for booting the Propeller.

*Peter*

Kaio

Dennis,

it should be possible to use a smaller EEPROM, if the size of your code does not exceed the EEPROM size. I have it not tried yet.
But the problem is, that you can not use the Prop Tool to program the EEPROM while it always write 32KB to EEPROM. So you need a special tool where you could be control the size to write the EEPROM.

Thomas

Forrest

You can use a Propeller without any EEPROM - the Prop Tool can program directly to the Propeller's RAM and run the program from there. The 24LC256 is widely stocked - Parallax sells it for $5 while most distributor's sell it for $2 to $3.

Dennis Ferron

Thanks. That's a good point you have about not needing an EEPROM if you just want to put the program in RAM with the Prop tool. That does therefore suggest the perfect use for my orphan Propeller chip: once upon a time, the first thing I did with my PropStick was put it on a breadboard and wire it up for use as a parallel EEPROM programmer. With the 32K of Propeller RAM, you don't have to come up with a half-baked scheme to transfer the parallel EEPROM data (bin file) from the PC to the Propeller. Instead, for parallel EEPROMs up to 16K, you can just include the binary file to be written out directly into the Propeller program along with a small bit of Spin that knows how to work the parallel EEPROM. Essentially, you use the Prop tool to transfer the bin file along with the Spin code. (There is a Spin directive for including a binary data file into the program.)

I've since taken apart that project to use my PropStick in other projects. But there is no reason it should require any propeller-EEPROM for the parallel-EEPROM-burner circuit; you just download a new program to the Propeller RAM every time you burn a new EEPROM. So I can use the bare Propeller chip to do it.

If you consider that the cost of the cheapest EEPROM burner I have been able to find for sale is $99, then being able to use a $12 Propeller and a breadboard is a very cost effective EEPROM burning solution.