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how to use a logic analyzer to determine the 8bit flash pin
Posted: February 14th, 2022, 14:07
by luojifenxiyi
Ladies and gentlemen, I am a newbie.
I would like to ask, how to use a logic analyzer to determine the 8bit flash pin definition.
D0, D1, D2, D3, D4, D5, D6, D7
RE, R/B, CE, WE, ALE, CLE.
Is there any technical information, or video instructions,
thank you all.
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 15th, 2022, 6:00
by pepe
you need to catch known commands like read ID and figure out the signals. Get yourself familiar with NAND flas docs and timing diagrams.
It's a good idea to analyze a known device first...
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 15th, 2022, 15:19
by fzabkar
I have zero experience in this area, but I would think that static resistance measurements would be useful.
For example, D0 - 7 would probably have very similar resistances to ground and Vcc. R/B is an open drain signal, so I would think that its resistance would be very high.
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 15th, 2022, 21:13
by pepe
I would expect the resistance of a 3state pin to be very high as well. Moreover, RB pins must have some pullup somewhere, which could make resistance lower. I would only expect some meaningful value in diode mode, but that also implies we would probably measure the ESD protection network...
The most informative check prior hooking up the LA is checking the suspected locations with an oscilloscope during power up of the device. Pads having no traffic are probably not interesting for us, at least not first
pepe
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 16th, 2022, 5:14
by arvika
1. Card you connected to LA has know pinout - very popular one. Find it.
2. Download and study datasheets from memory chips. You will find all information there. Look and compare signals based on know pinout.
3. Based on LA singals you paste on forum, probably you set wrong LA parameters to grab signals or have some shorts on wires.
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 16th, 2022, 13:01
by fzabkar
pepe wrote:Moreover, RB pins must have some pullup somewhere, ...
Yeah, that was a brain fart. Oops.
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 16th, 2022, 17:40
by luojifenxiyi
pepe wrote:you need to catch known commands like read ID and figure out the signals. Get yourself familiar with NAND flas docs and timing diagrams.
It's a good idea to analyze a known device first...
Hi I have found a solution, I will find it this weekend,
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 16th, 2022, 17:42
by luojifenxiyi
arvika wrote:1. Card you connected to LA has know pinout - very popular one. Find it.
2. Download and study datasheets from memory chips. You will find all information there. Look and compare signals based on know pinout.
3. Based on LA singals you paste on forum, probably you set wrong LA parameters to grab signals or have some shorts on wires.
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 16th, 2022, 17:44
by luojifenxiyi
fzabkar wrote:I have zero experience in this area, but I would think that static resistance measurements would be useful.
For example, D0 - 7 would probably have very similar resistances to ground and Vcc. R/B is an open drain signal, so I would think that its resistance would be very high.
Hi I have found a solution, I will find it this weekend, thank you. If the problem is solved, I will teach you the method
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 17th, 2022, 16:53
by luojifenxiyi
arvika wrote:1. Card you connected to LA has know pinout - very popular one. Find it.
2. Download and study datasheets from memory chips. You will find all information there. Look and compare signals based on know pinout.
3. Based on LA singals you paste on forum, probably you set wrong LA parameters to grab signals or have some shorts on wires.
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 17th, 2022, 16:54
by luojifenxiyi
- I have completed, successfully analyzed
fzabkar wrote:pepe wrote:Moreover, RB pins must have some pullup somewhere, ...
Yeah, that was a brain fart. Oops.
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 17th, 2022, 16:56
by luojifenxiyi
- I have completed, successfully analyzed
fzabkar wrote:pepe wrote:Moreover, RB pins must have some pullup somewhere, ...
Yeah, that was a brain fart. Oops.
- I have completed, successfully analyzed
I have completed, successfully analyzed
I have completed, successfully analyzed
Re: how to use a logic analyzer to determine the 8bit flash
Posted: February 18th, 2022, 3:43
by fzabkar
Nice work!