Re: PIC and EEPROM modules

coetzee.evert@xxxxxxxxx wrote:
On Jan 9, 2:17 pm, donald <Don...@xxxxxxxxxxxxxxxx> wrote:
coetzee.ev...@xxxxxxxxx wrote:
Hi guys
I'm currently using a PIC16F84 for a project. I need to use more
EEPROM than I have on the chip. So I'm considering adding a memory
module to store the additional data. I have no idea what my options
are, which will be the easiest to implement etc.
I dont even need the PIC to write the data to the EEPROM. I would like
to use my computer to program the EEPROM (max 1Mb) and then just use
the PIC to read it (I do the same currently with the PIC. Write EEPROM
data with the pic programmer and then read the data with the PIC).
I've been to microchip's website but I don't really get a noobguide to
what my choices are. Seems like there's at least two architechtures
I2C and SPI. Which will be best? Any suggestions?
Thanks
Some design considerations.

How many pins do you have left on the16F84 ?

How much code space do you have left in the16F84 ?

The16F84 does _not_ have an SPI or I2C controller on board.
You will need to bit-bang the lines to the external EEPROM.

With these assumption, what can you do with your design ?

Also, getting any data from your PC into the EEPROM.
Do you have an external programmer, do you want to code another PIC to
interface to a serial/parallel port on your PC.

Do you want to remove the EEPROM from the target board to reprogram it ?

All these things can be done, you need to make a decision about what you
want to do.

One last thing, are you programming in assembly or C ?

donald

Hi

I really have a quite simple program. So I'm flexible on changing pics
etc. I need to do something like a clock which plays a different tune
every 15 minutes. The tunes are stored in the memory. So I want to use
a computer to program the tunes into the memory module. If that
doesn't work I'm willing to program another chip to program the
memory, but I'd prefer to use the PC straight on the memory module. I
use a K149 USB hardware pic programmer. I use assembly (trying to keep
it elementary). I'm more than willing to remove the EEPROM to
reprogram.

Ok,

The design spec is to read a EEPROM device, thats been programmed somewhere else.

To help a little you can look at:
http://www.piclist.com/techref/microchip/i2c.htm



BTW: I know the DE command to program pic EEPROM from the PC. Can I
somehow program the pic memory RAM that way as well? It's REALLY
difficult to search in google for DE, DT and other 2character
commands. Does anyone have a link of how to program pic memory RAM (in
a similar way that you program EEPROM on the pic)


What does the DE command have to do with the EEPROM ??

If you picked out an EEPROM device and looked at its data ***, you would know by now.

Thanks!

good luck

donald
.