Pmod SF3 NOR Flash voltage ? 3.3V or 1.8V ?

[EMR]

Hi,

We bought Pmod SF3 NOR Flash for a 3.3V system. While debugging we found something incoherent on Pmod SF3 voltage.

All Digilent data mention 3.3V for Pmod SF3 : https://reference.digilentinc.com/reference/pmod/pmodsf3/reference-manual

On our SF3 module NOR Flash reference is 7ZA15 RW243.

On Micron web site, FBGA Code RW243 correspond to MT25QU256ABA8ESF-0AAT which is a 1.8V 256Mb flash chip.

We where expecting a 3.3V flash chip !

On the above post on these forum, the flash is mentioned to be MT25QL256ABA8ESF in replacement of N25Q original one.

https://forum.digilentinc.com/topic/18992-pmod-sf3-schematic-discrepancy/

MT25QL256ABA8ESF is indeed a 3.3V 256Mb flash chip. It's FBGA Code is RW201.

Shall we conclude that there are 3.3V and 1.8V versions of Pmod SF3 add-on boards ?

How can we differentiate those Pmod SF3 versions ?

Can we source the 3.3V Pmod SF3 somewhere ?

Thanks for you help,

EMR

[Bianca]

Hi @EMR,

You have the 3.3V version. FBGA is fine pitch ball grid array package. they chose a shorter code to identify each part number because it wouldn't fit on the capsule. However, the package you have on the PMOD is SOP2 16 as you can see from the part number: 

 

This is the part equipped on your pmod: https://www.digikey.ro/product-detail/en/micron-technology-inc/MT25QL256ABA8ESF-0AAT/MT25QL256ABA8ESF-0AAT-ND/8537532

 

I don't have a pmod SF3 in the office, but according to this document, you can see what each number means for the SOP2 package.

We don't have any PMOD operating below 3.3V.

 

I hope this helps.

Regards,

Bianca

 

 

[EMR]

Hi Bianca,

Thanks for your help. I found the numbering rules here https://www.micron.com/-/media/client/global/documents/products/customer-service-note/csn11.pdf

You have the picture of our SF3 module. As you can see the FBGA Code is RW243 which refers to MT25QU256ABA8ESF-0AAT. See micron tool, here https://www.micron.com/support/tools-and-utilities/fbga?fbga=RW243#pnlFBGA

This the mt25qU, not the mt25qL you mentioned.

According to Micron, MT25QL256ABA8ESF-0AAT has FBGA Code RW201 ( https://www.micron.com/support/tools-and-utilities/fbga?fbga=RW201#pnlFBGA ).

So what's true ?

Our module is powered in 3.3V, we can read flash device ID data but others read or write commands fails.

Regards,

EMR

[Bianca]

Hi @EMR,

Just the fact that you are able to read the device ID proves that the SPI is working that you have a clock and some data reading.

I've contacted the manufacturing department with the pictures you sent and they assured that this device is rated 2.7-3.6V. If the device would've been rated to 1.8V at this point you would not be able to read anything as the maximum rating for the 1.8 is 2.4V. At 3.3V it would be burned. 

I don't know if it's in some kind of writing protection mode, if it has any, or why you are not able to do other operations. I asked my colleague @JColvin to work with you on this, as I don't have a module in my office so I can't test it. 

Best regards, 

Bianca

[JColvin]

Hi @EMR,

What platform are you using to run the Pmod SF3? I tested the Pmod IP core that we have for the Pmod SF3 on Vivado 2018.2 with an Arty A7-35T and it successfully ran through all of the tests. Similarly, I tested the demo application (available on the Pmod SF3 Resource Center) that we have for a microcontroller (in this case, I used a Digilent WF32), and was able to successfully run through that demo as well without issue.

Thanks,
JColvin

[EMR]

Hi @JColvin,

Thanks for your tests.

We are using Pmod SF3 on a custom assembly of ZC706 Xilinx devkit and boards. SF3 is connected on daughter board. To avoid bring up problems, we first operate SPI at low frequency. Only ID reg read works. Yesterday, we switched Pmod SF3 to an ISSI Nor flash connected to the same place. This flash works fine.

Could you please share the part numbers/FBGA code of your SF3's flash ?

Thanks,

EMR

[JColvin]

Hi @EMR,

I have attached a picture of the part number present on my Pmod SF3. I asked our contact here at Digilent about the specific part number and they informed me that original part number for the Pmod SF3 was a Numonyx N25Q256A13ESF40G IC which matches the what datasheet reports(direct download link to the corresponding Micron datasheet, with part number information on page 88, Table 43). That particular part went EOL though so it was replaced with a Micron MT25QL256ABA8ESF.

I do agree that the RW243 labeling shown on your Pmod directs to the MT25QU256ABAESF rather than the MT25QL256ABAESF, though if you if you can successfully read the device ID, then as @Bianca mentioned, you would not have been able to read the ID code as the U variant only has an absolute maximum voltage rating of 2.4V, it would have definitely been fried if it were that component rather than one that can handle 3.3V. I will order a fresh Pmod SF3 to see if it matches your marking and performs differently in any way though.

Are you using a custom "library" to communicate with the flash chip?

Thanks,
JColvin

[EMR]

Hi @JColvin,

Thanks for the part numbers and explanations. We also thought we had burn the flash but not.

We use a third-party QSPI controller and a custom driver. We hadn't yet look at the reference designs you mentioned in your first post but we'll do the comparison.

Thanks,

EMR