Having problem with writing eeprom memory

Thread Starter

Novacicm

Joined Aug 12, 2017
5
I am trying to write atmel at28c256 on breadboard so I tied all address lines to ground, and all I/O lines also tied to ground. I untie I/O lines for reading, tie 'WE to high, 'CE to low, and 'OE to low for reading. I am reading all ones at I/O ports, no matter what address. So, when I try to write this eeprom I put 'OE high and with 'WE line I touch to ground so that should write stuff to memory but it does not, all I/O ports were connected. I also made small RC circuit with button on WE but that also does not work. Any toughts?
 

jayanthd

Joined Jul 4, 2015
904
I am trying to write atmel at28c256 on breadboard so I tied all address lines to ground, and all I/O lines also tied to ground. I untie I/O lines for reading, tie 'WE to high, 'CE to low, and 'OE to low for reading. I am reading all ones at I/O ports, no matter what address. So, when I try to write this eeprom I put 'OE high and with 'WE line I touch to ground so that should write stuff to memory but it does not, all I/O ports were connected. I also made small RC circuit with button on WE but that also does not work. Any toughts?

Provide more details. What micrcontroller and Compiler are you using. What is the Crystal frequency ? Zip and post your complete C Project.
Show your circuit. Show your breadboard circuit image. If you have Proteus then draw circuit in Proteus and zip and post it here.

I can help you with proper code. It is an I2C eeprom.
 

Thread Starter

Novacicm

Joined Aug 12, 2017
5
Provide more details. What micrcontroller and Compiler are you using. What is the Crystal frequency ? Zip and post your complete C Project.
Show your circuit. Show your breadboard circuit image. If you have Proteus then draw circuit in Proteus and zip and post it here.

I can help you with proper code. It is an I2C eeprom.
I am not using any micrcontroller, I am jus trying to program memory on a breadboard, I am trying to make jus like ben eater did in this vid, schema is like his on vid, I do not have schema in any program.
Thank you for reply.
 

Thread Starter

Novacicm

Joined Aug 12, 2017
5
Please upload your schematic as a 800x600 .jpg file.
I am not using any micrcontroller, I am jus trying to program memory on a breadboard, I am trying to make jus like ben eater did in this vid, schema is like his on vid, I do not have schema in any program.
 

jayanthd

Joined Jul 4, 2015
904
I am not using any micrcontroller, I am jus trying to program memory on a breadboard, I am trying to make jus like ben eater did in this vid, schema is like his on vid, I do not have schema in any program.
Thank you for reply.
Ok. I checked the datasheet. It is an Parallel Interface eeprom and not I2C eeprom. I will make a circuit for you.
 

jayanthd

Joined Jul 4, 2015
904
Okay, thank you.
For AT28C256 there is no max Write Pulse Width time. So, you can omit the RC circuit and just use a button with 10k resistor and apply 5V through button circuit to WR pin for say 1 or 2 sec.

I checked Proteus but it doesn't have a working model for 28Cxxx EEPROMs.

I will provide a example circuit for your EEPROM tomorrow after creating a schematic only model in Proteus.
 

Thread Starter

Novacicm

Joined Aug 12, 2017
5
For AT28C256 there is no max Write Pulse Width time. So, you can omit the RC circuit and just use a button with 10k resistor and apply 5V through button circuit to WR pin for say 1 or 2 sec.

I checked Proteus but it doesn't have a working model for 28Cxxx EEPROMs.

I will provide a example circuit for your EEPROM tomorrow after creating a schematic only model in Proteus.
Yeah I already saw there is no max write pulse, but I already tried tieing WE direct to ground than back to 5V but still same problem. I will also try circuit without RC just like you said.
Thank you.
 
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