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bal_square
Joined: 05 Dec 2018
Posts: 11
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 Posted: Fri Dec 07, 2018 1:01 pm |
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| Ttelmah wrote: | You are still not showing a crystal in the circuit. Also the ENVREG pin needs
to be tied to Vdd.
Also look at Figure 2-1. This shows the minimum connections required for the PIC to work.
You need to check that the chips are both receiving the right supply. The way that Proteus hides the supply pins and can then connect the wrong supply (with no standard for voltage levels and names existing), can easily lead to a chip not being powered,
Big question is whether the Proteus model of the memory actually works....
Unfortunately they often don't. I'd say at least 10% of parts have significant
issues in Proteus.
It is a very poor simulator, and people relying on it are most of the time
wasting their time...
The SO pin will not be driven till CS is low. |
It's very strange...I checked SI(yellow line) and SCK(blue line), It sends signals correctly, but flash memory doesn't respond. 
Last edited by bal_square on Fri Dec 07, 2018 2:24 pm; edited 1 time in total |
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temtronic
Joined: 01 Jul 2010
Posts: 9245
Location: Greensville,Ontario
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| Posted: Fri Dec 07, 2018 2:05 pm |
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I'd try another memory device. Originally you attached it to an 877, a 5 volt PIC, so it could easily now be defective.
Your 'link' didn't work for me, came back '404'
Jay |
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bal_square
Joined: 05 Dec 2018
Posts: 11
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| Posted: Fri Dec 07, 2018 2:24 pm |
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| temtronic wrote: | I'd try another memory device. Originally you attached it to an 877, a 5 volt PIC, so it could easily now be defective.
Your 'link' didn't work for me, came back '404'
Jay |
Sorry, corrected |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Dec 07, 2018 6:23 pm |
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| temtronic wrote: | I'd try another memory device. Originally you attached it to an 877, a 5 volt PIC, so it could easily now be defective.
Jay |
The Proteus model could be defective. He is not using an actual chip. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19550
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| Posted: Sat Dec 08, 2018 2:18 am |
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Agreed. I suggested this earlier.
Also, his Proteus oscilloscope 'plot', does not show the CS line, or have a high enough sample rate to actually see what is being clocked out. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19550
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| Posted: Sat Dec 08, 2018 8:19 am |
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Have done a little checking.
People are using the Proteus model OK, but all say you must _write_ to the chip before the Proteus model will support a read. |
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temtronic
Joined: 01 Jul 2010
Posts: 9245
Location: Greensville,Ontario
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| Posted: Sat Dec 08, 2018 8:47 am |
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I was curious, so downloaded the EEPROM datasheet...
tidbits of information that must be noted...
WRITE ENABLE (WREN): The device will power up in the write disable state when VCC
is applied. All write instructions must therefore be preceded by the WREN instruction.
PROGRAM (PROGRAM): In order to program the AT25F4096, two separate instructions
must be executed. First, the device must be write enabled via the WREN
instruction. Then the Program instruction can be executed.
I don't have the chip, but it seems your 'driver' needs to implement these details or instructions...
Jay |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19550
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| Posted: Sat Dec 08, 2018 10:09 am |
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Yes, but not unless he writes to the memory.
The read instruction on a real chip, will work without WREN.
As I say though people are reporting that you cannot read from the Proteus
chip until you have written to it (their model seems not to actually support
reading from a 'blank' chip). To do a write, the driver will have to enable
writing.
I found a poster complaining that a read did not work in Proteus, and
somebody advised him to write first, and he reported back that it did then
work. |
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bal_square
Joined: 05 Dec 2018
Posts: 11
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| Posted: Sat Dec 08, 2018 11:48 am |
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| Ttelmah wrote: | Yes, but not unless he writes to the memory.
The read instruction on a real chip, will work without WREN.
As I say though people are reporting that you cannot read from the Proteus
chip until you have written to it (their model seems not to actually support
reading from a 'blank' chip). To do a write, the driver will have to enable
writing.
I found a poster complaining that a read did not work in Proteus, and
somebody advised him to write first, and he reported back that it did then
work. |
YES, a lot of thanks, You're my hero. IT works. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19550
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| Posted: Sat Dec 08, 2018 12:48 pm |
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You now perhaps understand a little of why we are so scathing of Proteus...
It is very much 'not a good way' of finding how electronics will actually
behave.  |
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