View Full Version : Increasing the size of a EEPROM
01-15-2006, 03:03 AM
I am using a BS2-OEM, with a socketed 24LC16B, and would like to replace it with an Atmel·24C64A. I thought they are pin for pin compatable, but the PIC16C57-HS/P does not recognize the 24C64A. Can you suggest how I can use the·larger capacity 24C64A, or any other EEPROM?
Also, I have an earlier posting, that you have given me an excellent answere for, that I would like to delete from your forum but don't know how to do it.
01-15-2006, 03:27 AM
The BS2 is programmed to store the PBASIC program in a 2KB EEPROM - you can't alter this. You CAN store data on a seperate EEPROM. Nuts & Volts #115 shows you how to do this www.parallax.com/dl/docs/cols/nv/vol5/col/nv115.pdf (http://www.parallax.com/dl/docs/cols/nv/vol5/col/nv115.pdf)
If your program doesn't fit into the original EEPROM, then you'll need to switch to one of the other BS2 versions that supports 16KB for programs such as the BS2SX, BS2PX, etc
01-16-2006, 08:07 AM
Thank you for your response. Based on the information I obtained from the Parallax web site, a SX28AC/DP interperter chip is used in the BS2SX OEM board. The schematic for the BS2SX, using the SX28AC/DP,·is the same as the BS2, using the PIC16C57C. Since the pin-out for the two·interperters is the same, can I substitute the SX28AC/DP into·my BS2-OEM so I can use a higher capacity EEPROM? I realize that I would have to get the SX28AC with the installed proprietary code from Parallax.
01-16-2006, 10:02 AM
·· I don't think you understand, the interpreter (The proprietary code on the chip) is written to only address that much space.· If you want more EEPROM space you can either purchase or build an OEM BASIC Stamp 2e, 2sx, 2p, 2pe or 2px.· That is the only way.· You cannot just put a bigger EEPROM on and it works.· It's not like adding RAM to your PC.
Parallax Tech Support
01-16-2006, 10:21 AM
The Interpreter chip in the BS2 OEM is a wide 28 pin chip, while the BS2SX interpreter chip is a narrow 28 pin chip - so it's not a drop in replacement. I haven't looked at the schematics, but I know the resonators are also different (20 MHz vs 50 MHz for the BS2SX).