please help in interfacing at24c256 and parallel port

Thread Starter

efm

Joined Sep 14, 2006
14
hello,

i'm trying to write and read my at24c256 eeprom through parallel port. i have schematics from
atmel (interfacing at24c32 and 8051), from www.phanderson.com/printer/24c32 (interfacing at24c32
and parallel port), and from mcmcc.bat.ru/serp (at24cxx and parallel port), but none of them is
working.

please could someone let me know how to wire the at24c256 and parallel port, with simple
program (just for reading and writing a byte), or at least point me to a website that covers this thing.

btw, i'm using SuSE 10.

please help,

faizal
 

beenthere

Joined Apr 20, 2004
15,819
Hi,

Given the amount of material presented at the web site, things should work. Have you compared the spec sheet on the 256 device with the example 24C23 serial eprom? There could be significant differences.

Can you post up a schematic of your circuit? Also, you may be running Suse10, but on what hardware platform? How is the parallel port configured?
 

Thread Starter

efm

Joined Sep 14, 2006
14
hello,
thanks for the reply,

hmm...there is some differences between at24c32 and at24c256...
on at24c32, the pins 1, 2, and 3, are labeled A0, A1, A2 (address pin), while on the
at24c256, they're labeled A0, A1, and NC...will this be a problem? because in every schematics
those pins are grounded,

here is the features of at24c32:
Rich (BB code):
Features
• Low-Voltage and Standard-Voltage Operation
    – 2.7 (VCC = 2.7V to 5.5V)
    – 1.8 (VCC = 1.8V to 5.5V)
• Low-Power Devices (ISB = 2 µA at 5.5V) Available
• Internally Organized 4096 x 8, 8192 x 8
• 2-Wire Serial Interface
• Schmitt Trigger, Filtered Inputs for Noise Suppression
• Bidirectional Data Transfer Protocol
• 100 kHz (1.8V, 2.5V, 2.7V) and 400 kHz (5V) Clock Rate
• Write Protect Pin for Hardware Data Protection
• 32-Byte Page Write Mode (Partial Page Writes Allowed)
• Self-Timed Write Cycle (10 ms max)
• High Reliability
    – Endurance: 1 Million Write Cycles
    – Data Retention: 100 Years
• Automotive Grade and Extended Temperature Devices Available
• 8-Pin JEDEC PDIP, 8-Pin JEDEC SOIC, 8-Pin EIAJ SOIC,
  and 8-pin TSSOP Packages
and the features of at24c256:
Rich (BB code):
Features
• Low Voltage and Standard Voltage Operation
    – 5.0 (VCC = 4.5V to 5.5V)
    – 2.7 (VCC = 2.7V to 5.5V)
    – 1.8 (VCC = 1.8V to 3.6V)
• Internally Organized 16,384 x 8 and 32,768 x 8
• 2-Wire Serial Interface
• Schmitt Trigger, Filtered Inputs for Noise Suppression
• Bidirectional Data Transfer Protocol
• 1 MHz (5V), 400 kHz (2.7V) and 100 kHz (1.8V) Compatibility
• Write Protect Pin for Hardware and Software Data Protection
• 64-Byte Page Write Mode (Partial Page Writes Allowed)
• Self-Timed Write Cycle (5 ms typical)
• High Reliability
    – Endurance: 100,000 Write Cycles
    – Data Retention: 40 Years
    – ESD Protection: > 4000V
• Automotive Grade and Extended Temperature Devices Available
• 8-Pin JEDEC PDIP, 8-Pin JEDEC and EIAJ SOIC, 14-Pin TSSOP, and
  8-Pin Leadless Array Packages
the first schematic, scheme.jpg, i got from http://mcmcc.bat.ru/serp,
and the second, myscheme.jpg is my design, i just delete the 93xxx because i don't use it

thank you
 

Attachments

beenthere

Joined Apr 20, 2004
15,819
Hi,

What is the purpose of the address pins? In the serial programmer schematic, they are shown floating - neither tied high or low.

Assuming the address pins may be ignored, what are the protocols for setting up the serial eprom for reading out data, or for writing data in? I'm sure you'll have to tell the chip what to do before it will work. Also - did you notice that the write cycle on the 256 device is twice as fast as the 32? That could affect something.
 

Thread Starter

efm

Joined Sep 14, 2006
14
hello beenthere,

the a0, a1, and a2 is for chip selection i guess. if you wire seven more of that chip together, then the
selection of which chip to store the data is through those pins. the datasheet says that they're low by
default if they're not tied.

hmm..i didn't notice the write cycle before...that could be a problem...
i just bought another 24c256 and some 24c32s, in case that mine is broken,
i'll try them tonight...

thank you,

faizal
 
Top