MultiDrive – free backup, clone & wipe disk utility from Atola Technology

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: Dumping the EEPROM
PostPosted: September 16th, 2009, 21:49 
Offline
User avatar

Joined: September 8th, 2009, 18:21
Posts: 16955
Location: Australia
Somewhere in the sticky threads is a discussion which shows how to dump the contents of a serial EEPROM using a device programmer and an SOIC chip clip.

It seems to me that the programmer is powering everything on the PCB that connects to the same supply rail. I wonder why that doesn't trigger the programmer's overcurrent detection/protection logic.

Secondly, how can one be certain that the MCU is not competing with the programmer for access to the EEPROM? In my ADSL modem, for example, when its serial EEPROM is being externally programmed, the PCB's reset line is held low, thus tristating the CPU.

Does the MCU read the EEPROM on power-up, transfer the contents to RAM, and then ignore it until the next power cycle?

_________________
A backup a day keeps DR away.


Top
 Profile  
 
 Post subject: Re: Dumping the EEPROM
PostPosted: September 16th, 2009, 22:25 
Offline

Joined: June 9th, 2008, 12:06
Posts: 213
Depends on the EEPROM you are talking about as well as the programmer used, AND ALSO, the PCB. Personally, I use an adapter that has basic capacitors, resistors, etc. to allow writing to serial EEPROM, regardless of interference from nearby circuits. Worst cases, you can cut one leg of EEPROM only, then solder back when done. FAST. EASY.

_________________
http://pcrecoveryllc.com


Top
 Profile  
 
 Post subject: Re: Dumping the EEPROM
PostPosted: September 17th, 2009, 14:13 
Offline

Joined: July 18th, 2006, 3:05
Posts: 7476
Location: ITALY
...or desolder with SMD equipment, read in programmer through SO/SOIC adapter, resolder. Safer and professional. We have all the time in the world (now) ...


Top
 Profile  
 
 Post subject: Re: Dumping the EEPROM
PostPosted: September 17th, 2009, 17:13 
Offline

Joined: January 8th, 2008, 5:21
Posts: 927
Location: uk
Sometime you don't even need a programmer!

For a 93C* series eeprom you can connect the chip directly to the parallel port.
It will usually work with the ic in circuit. Just solder the leads to each pin.
Something like this:
1 (CS) pin 3 (D1)
2 (CLK) pin 5 (D0)
3 (DI) pin 6 (D2)
4 (D0) pin 12 (ACK)
5 (Vss) pin 23 (GND)
6 ( " ) pin 23 (GND)
7 (N/C) none
8 (Vcc) pin 2 (D3)


Top
 Profile  
 
 Post subject: Re: Dumping the EEPROM
PostPosted: September 18th, 2009, 3:04 
Offline

Joined: July 18th, 2006, 3:05
Posts: 7476
Location: ITALY
It's a "Wile E. Coyote" solution : if you don't have grounded and fine tip soldering iron and adequate wires you will most likely damage the pcb, especially on some materials used on some drives... *cough! cough!*


Top
 Profile  
 
 Post subject: Re: Dumping the EEPROM
PostPosted: September 18th, 2009, 6:30 
Offline

Joined: January 8th, 2008, 5:21
Posts: 927
Location: uk
BlackST wrote:
It's a "Wile E. Coyote" solution : if you don't have grounded and fine tip soldering iron and adequate wires you will most likely damage the pcb, especially on some materials used on some drives... *cough! cough!*
Yes a grounded temperature controlled Weller iron with a ptr8 tip.
A magnifying lamp.

If I have any concerns I sometimes remove the chip with hot air and then solder on the leads for reading/programming. And then I replace the chip.
I find it easier and quicker than using the Willem and i've never had any problems using this method.

And yes you would need top quality soldering skills to achieve good results and not cause any damage. I am very confident of my own skills in this department.


Top
 Profile  
 
 Post subject: Re: Dumping the EEPROM
PostPosted: September 18th, 2009, 10:15 
Offline

Joined: July 18th, 2006, 3:05
Posts: 7476
Location: ITALY
I am quite always right : the problem is that people don't understand, and they think it is simple even with a quick soldering gun or "Joe's Hardware store " china quality 5$ soldering iron...

Sometimes , something goes wrong even with my professional tools (PCB tend to delaminate especially if new Pb Free alloy is used) or a track needs to be repaired later... we call it "SFIGA" (a stroke of bad luck , or practical demonstration of Murphy's law).


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: Google [Bot] and 55 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group