I have seen/used simple examples of using a single external EEPROM, and know that these can be chained together, but have not seen any posts on the subject, I want to check my thinking with those who know here..

I have two 24LC515 512kbit chips, and want to use them to store data for a logger. The object of the device is to log inbound data in 35bit long data points, coming in one per second. At 512kb this is roughly 30 minutes of storage, at 1Mbit it is 1 hour, and I need an hour.

Question is, HOW to address two/more of these devices? The MCP data sheets discuss the addressing works, but PBP does not address the 'Chip Select Bits' deeply enough for me to really grock it.

Control bits for this unit is '1010'.

Next bit is 'block select bit' - which does not sound like I need to address.(?)

The two are 'Chip Select Bits' - which "Must correspond with the A0 and A1 logic levels' - so I assume that means tying these two pins high or low physically on the board (right?), for example:

Chip 1 - A0=VCC, A1=VDD
Chip 2 - A0=VCC, A1=VCC
Chip 3 - A0=VDD, A1=VCC
Chip 4 - A0=VDD, A1=VDD

So I can see how the system might tell the chips apart based on this.

I THINK the way to do this must be to format Symbols for these different chips?

symbol chip1 = %1010x01x ' what is 4th and 1st value supposed to be?
symbol chip2 = %1010x00x ' what is 4th and 1st value supposed to be?

then when writing to these, the appropriate chip would respond.. ie, if chip 2 sees the chip select as '00' it responds, and chip 1 ignores. (Right?)

SO.. Physically -- are the pins of SDA, SCL, VDD, and VCC tied together on these chips??

Sorry for the rambling questions.. I hope someone can shed some light on things:

1. What is the proper setup for multiple chips ; %1010x01x ?? or what?
2. Are the external eeproms physically tied on pins A0 and A1 to set their address?
3. Do they all share the same bus lines?
4. What is the PBP command setup for dealing with multiple units? Does my program logic deal with EACH CHIP, or does PBP make both of them into one big memory bank, and I don't have to worry about the two units?
5. If Do have to worry about the two units then I need to be intelligent about using one up, then jumping to the other, then remembering where I put things when I go to get them back.... Right?

Thanks!

Tom