Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

simple question about new eprom?

Status
Not open for further replies.

Moss

Full Member level 3
Joined
Jul 24, 2001
Messages
170
Helped
9
Reputation
18
Reaction score
2
Trophy points
1,298
Activity points
1,631
When the eprom(27C512) is new , all bytes are FF? Corect?
 

mr_ghz

Full Member level 5
Joined
Apr 1, 2002
Messages
289
Helped
7
Reputation
14
Reaction score
5
Trophy points
1,298
Activity points
3,551
Hi Moss,

Yes, you're right. An unprogrammed EPROM cell (no charge on the gate)
gives a logic '1'. If you put charge on this gate (programming), the
corresponding bit changes to '0'. With UV-Light (ionizing the air), this
charge can be removed and the bit changes back to '1'.
Without UV-Light the charge lasts for many years (data rentention),
normally >10 years fo old EPROM's newer normally >100 years.

Bye
 

BENOIT

Member level 5
Joined
Sep 22, 2001
Messages
89
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
France
Activity points
1,903
Note that Cypress Eproms have 00 inside when Blank.
MB.
mr_ghz said:
Hi Moss,

Yes, you're right. An unprogrammed EPROM cell (no charge on the gate)
gives a logic '1'. If you put charge on this gate (programming), the
corresponding bit changes to '0'. With UV-Light (ionizing the air), this
charge can be removed and the bit changes back to '1'.
Without UV-Light the charge lasts for many years (data rentention),
normally >10 years fo old EPROM's newer normally >100 years.

Bye
 

Moss

Full Member level 3
Joined
Jul 24, 2001
Messages
170
Helped
9
Reputation
18
Reaction score
2
Trophy points
1,298
Activity points
1,631
Thanks both of you!
My chips are ST, so new must be filled with FF.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top