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 getting 27c4001 to read like 27c1001		  New Topic  Reply to Topic
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mdr14

3 Posts
Posted - 10/23/2015 :  20:00:02  Show Profile  Reply with Quote
I want the 4 meg 27c4001 to read like a 1 meg 27c1001. do i just change the device offset to ?
Edited by - mdr14 on 10/23/2015 21:39:58
Reply #1

ZLM

2937 Posts
Posted - 10/23/2015 :  22:45:07  Show Profile  Reply with Quote
You do not need to set anything. Just load the 27C1001 data into software and program the 27C4001 should work.
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Reply #2

mdr14

3 Posts
Posted - 10/24/2015 :  19:28:01  Show Profile  Reply with Quote
Well, yes. It will write the chip no problem...
But I need to write to the 4 meg chip so it looks like a 1 meg chip.
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Reply #3

ZLM

2937 Posts
Posted - 10/27/2015 :  13:10:44  Show Profile  Reply with Quote
Yes. it looks like 1 meg chip. You can use your 1 meg chip data and write to 4 meg chip without change anything. Put the 4 meg chip into your machine and it will work.
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Reply #4

mdr14

3 Posts
Posted - 11/05/2015 :  16:08:36  Show Profile  Reply with Quote
ZLM, Trust me, I appreciate your responses. But I am not getting the answer I need from you. I need a 1 meg chip in place. not the 4meg. The machine I am installing them in wont recognize the 4 meg. I need the machine to think it is a 1 meg.
I have done this before where I needed a 1 meg to read like a 512k. I had to change the offset.
My memory sux so I don't remember what I did. I have change the offset. I don't know what value I need to use.

Thanks!!!
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Reply #5

ZLM

2937 Posts
Posted - 11/07/2015 :  19:02:00  Show Profile  Reply with Quote
You do not need to set the offset. Write the 1 Meg data into 4 Meg chip. And then place the 4 meg chip into your machine. Your machine will think it is the 1 meg chip.
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Reply #6

anniel

2540 Posts
Posted - 11/19/2015 :  15:45:55  Show Profile  Reply with Quote
Pin 30 and pin 31 are held hi or low in your application? Don't forget those are address lines on the 27c4001.
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Reply #7

ZLM

2937 Posts
Posted - 11/21/2015 :  17:21:41  Show Profile  Reply with Quote
The pin 30,31 address lines will change if the data size exceed the 27c1001 size.

If you load the 27C1001 data from address 000000, then they do not change while programming and stay low.
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Reply #8

anniel

2540 Posts
Posted - 11/24/2015 :  05:23:12  Show Profile  Reply with Quote
Yes ZLM, but on the board if left floating or held high the application may try to read inexistant data
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