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Otr8
USA
2 Posts |
 Posted - 11/19/2023 : 21:52:15
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Hello guys,
I have been trying to figure out an issue for a couple days now. I have some TMS27C240 EPROMs, which I all purchased brand new. I am running the ROMs at 5V. They would run normally until the voltage at input pin A9 switches from 0 to 5V. During this event, all outputs would fluctuate thereby disturbing all of my control lines. And yes, ALL inputs are stably connected, nothing is floating.
I read in the datasheet that A9 can be driven to 12V in the signature mode(Which I am not intending to use at all). At this point I do not know whether my GQ-4x4 is the culprit, and is somehow messing up the input structure while writing.
A detail that might be useful is that the I programmed the ROM so that the output is the same whether A9 is on or off. Could you please guide me on what I might be doing wrong?
Below is a link to the datasheet(Page and 5 mention the mention the mode using A9 at 12V). For whatever reasons I cannot attach a file to the post.
https://pdf1.alldatasheet.com/datasheet-pdf/view/92075/TI/TMS27C240.html
Thank you in advance for your help! |
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| Reply #1
anniel
2572 Posts |
Posted - 11/20/2023 : 06:59:59
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quote:
Originally posted by Otr8
Hello guys,
I have been trying to figure out an issue for a couple days now. I have some TMS27C240 EPROMs, which I all purchased brand new. I am running the ROMs at 5V. They would run normally until the voltage at input pin A9 switches from 0 to 5V. During this event, all outputs would fluctuate thereby disturbing all of my control lines. And yes, ALL inputs are stably connected, nothing is floating.
I read in the datasheet that A9 can be driven to 12V in the signature mode(Which I am not intending to use at all). At this point I do not know whether my GQ-4x4 is the culprit, and is somehow messing up the input structure while writing.
A detail that might be useful is that the I programmed the ROM so that the output is the same whether A9 is on or off. Could you please guide me on what I might be doing wrong?
Below is a link to the datasheet(Page and 5 mention the mention the mode using A9 at 12V). For whatever reasons I cannot attach a file to the post.
https://pdf1.alldatasheet.com/datasheet-pdf/view/92075/TI/TMS27C240.html
Thank you in advance for your help!
Did you test the programmer? |
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| Reply #2
Otr8
USA
2 Posts |
Posted - 11/20/2023 : 15:37:11
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quote:
Originally posted by anniel
Did you test the programmer?
How do I go about doing that?
After programming my .bin files into the ROMs, I read the ROMs contents and compare it with the original(through) code, and they always match. |
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| Reply #3
anniel
2572 Posts |
Posted - 11/21/2023 : 10:16:07
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quote:
Originally posted by Otr8
quote:
Originally posted by anniel
Did you test the programmer?
How do I go about doing that?
After programming my .bin files into the ROMs, I read the ROMs contents and compare it with the original(through) code, and they always match.
In the menu bar select "Test H/W" then "Test H/W" again. |
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TMS27C240 address pin A9 crashing output
