Looking for a 28hc64 writer

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I folowing this video to use an arduino uno to write in an EEPROM (to use in an 6502)

https://www.youtube.com/watch?v=...

the problem is , im using an x28hc64, but dont work, the arduino read all zeros, and if i apply pressure on the 28hc64 i get random values in the write, so i ask, there is an programmer hardware to write this eeprom? The minipro Tl866cs price is too high for me in a hoblish project

Last Edited: Wed. Sep 29, 2021 - 08:05 PM
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Welcome to AVRFreaks!

staltux wrote:
if i apply pressure on the 28hc64 i get random values in the write

As you have found, breadboards suck, the quality varies alot, so it is no surprise that you will have flaky connections.

Please post a picture of your setup, a freak may be able to spot some of the trouble.

Have you made adjustments for the different size eeprom you are trying to program as it differs from the one in the video. i.e. number of address lines?

 

Jim

 

 

 

Keys to wealth:

Invest for cash flow, not capital gains!

Wealth is attracted, not chased! 

Income is proportional to how many you serve!

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Hi Jim, yes I made adjustments because my chip have A0 to A12 address lines (8k eeprom), there is some pictures, no matter what i try to write this time, I get random data has in the last picture

ps: using Gallery feature of the forum give me You are not authorized to access this page. so the picture is attached

 

Attachment(s): 

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Where are all of your capacitors for your chips power pins?? please don't say you forgot them!!!

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

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i cannot forget what i dont know ¯\_(ツ)_/¯
but seriously powering from 5v of arduino , i need capacitors?

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i need capacitors?

YES!  wink Particularly with older chips. Close to the power pins, ALL of them.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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You need capacitors, that is how 28HC64 works: only when signal changes, the current for very short time may reach nnn mA.

But, there is another danger I do not know how serious- all that obsolete memories are static sensitive, so be careful to not touch open pins with hands. Apply power when all is connected, good luck.

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js wrote:

i need capacitors?

YES!  wink Particularly with older chips.

and particularly on breadboards - when you can have some pretty high-resistance connections ...

 

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the digitalWrite(low/high) by then self dont change the current and the signal?

And I dont understang what is the need for a  capacitor here, is for protect from high voltaget peak? The arduino dont do this job converting energy from the usb port ?
 

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I dont understang what is the need for a  capacitor here

For very small amount of time  (nano seconds) during the high to low transitions or vice versa, a largish current is drawn by the 2 output transistors of FETs  of the gate as they change state (you can imagine both devices on, PNP and NPN).

 

The 100nF caps will handle that current, larger caps will not do the job as their internal impedance is too high.

 

This is logic theory 101 and has been around for about 50 years. smiley

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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js wrote:
This is logic theory 101 and has been around for about 50 years.

And this is why you cannot skip the theory and go direct to pratice laugh, thank you

Another question, this is the same theory behaind the use of  22pF  in crystal clocks?
I willl order the capacitors and a new eeprom to test and see if i dont have damage he old one in the breadboard.

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you cannot skip the theory and go direct to pratice

I did when I was young and impatient and I learned a lot the from university of life, very hard lessons. When things failed I had to go back and read books, but that was many decades ago.

 

this is the same theory behaind the use of  22pF  in crystal clocks?

There are good formulas to work out the exact value depending on crystal specs etc. but I have usually used what the manufacturer specifies or near enough.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Has I said, i ordered the capacitors and other chip, but meanwhile i found a 22pf in a box and think, what if? If the thing dont explodes i am fine.
Well, using it in the eeproom eliminate the random noise, now no matter what i try to write the eeproom gives me all zeros, no more random data, is not the fix, but an improvement laugh
i will wait 2 week for the shipment frown

Any guest what else making the write to fail?

Last Edited: Thu. Sep 30, 2021 - 03:25 AM
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What code are you using to program the EEPROM?  You are shifting the EEPROM address out from the AVR using 74HC595 chips.  Are you getting the right address on the EEPROM pins? Are you writing 64 bytes and then doing a page memory write?

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https://www.tindie.com/products/...

Arduino shield should make reading/programming easy!

 

 

Keys to wealth:

Invest for cash flow, not capital gains!

Wealth is attracted, not chased! 

Income is proportional to how many you serve!

Lets go Brandon!

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Simonetta wrote:

What code are you using to program the EEPROM?  You are shifting the EEPROM address out from the AVR using 74HC595 chips.  Are you getting the right address on the EEPROM pins? Are you writing 64 bytes and then doing a page memory write?

 

What code are you using to program the EEPROM?

this code, ommiting lines from 106 to 115
https://github.com/beneater/eepr...

 

You are shifting the EEPROM address out from the AVR using 74HC595 chips

Yes

 

Are you getting the right address on the EEPROM pins?

yes, checked with leds

 

 

Are you writing 64 bytes and then doing a page memory write?

looking at the code and the datasheet, no, the code set adress(shiftout) on every write, so i think is not in the 150μs range

the write is byte by byte

 

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ki0bk wrote:

https://www.tindie.com/products/...

Arduino shield should make reading/programming easy!

 

 

thanks, saved for later, international shipping to here, maybe i buy one after i can fix and understand why the non shield way is not working, or assemble one myself

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the cip arrives, same result, changed to an arduino mega, same result

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Unfortunately, all it takes is one wire put in the wrong spot, or one board connection acting flaky & you may get strange results or even no results.

 

Do you have a scope or analyzer to verify what the chip is actually getting right at the EEPROM pins (NOT the breadboard--use the chip pins, they are what counts)

 

It is to tough to diagnose from here with a blizzard of wires.

 

Your VCC strip looks like it goes to lots of chips---but where/how does the strip get power?

Schematic?

 

Either you will have luck or a long road...get a bag of doughnuts before you go.

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Wed. Oct 6, 2021 - 03:10 AM
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It looks like the code waits only 10ms between writing bytes, is this time OK for the EEPROM you have? I vaguely remember something like 50ms between bytes.

 

    digitalWrite(WRITE_EN, LOW);
    delayMicroseconds(1);
    digitalWrite(WRITE_EN, HIGH);
    delay(10);    ///Delay between bytes??

Of course you need to make sure that the clock frequency is the same for your board.

 

edit looks like the EEPROM has a self timed write and typically a 2ms write cycle, so 10ms wait should be fine.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

Last Edited: Wed. Oct 6, 2021 - 04:00 AM
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all the powers pins go to the breadboard, the breadboard get the power from the 5v pin of the arduino, same for the ground, no external power supply

i tryed others delay times (1 , 2, 10, 50 ms) but no aval
 

Unfortunately i dont have a scope, i will try one thing, attach the chip to a socket and solder the jump wires direct in the socket lags, skipping the breadboard part to remove this variable