Compatibility between CY15B004Q-SXE and FM25V10 F-RAMs

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
RicardoALFCG
Level 1
Level 1
First reply posted First question asked Welcome!
Hello, 
 
I have been using FM25V10 for a long time, however, and due to the shortage, I had to replace this FRAM to a semi-compatible one which is the CY15B004Q - datasheets links attached. I am struggling to get this FRAM working and something is missing on my side for sure. So, I've decided to query on this forum you with the hope you can enlightening me with some information that can help me.
 
From my analysis, the major differences are the following:
  • CY15B004Q does not have unique SN features, neither the OP commands regarding to this functionality.
  • CY15B004Q does not allow fast reads or writes.
  • CY15B004Q has only 4Kbit (512 * 😎 instead of 1Mbit (128k * 8).
  • CY15B004Q has a logic bug in the state machine, where the OP code byte 0x0A does not trigger clearing the WEL bit.
  • CY15B004Q has 0 - 16 Mhz speed instead of FM25V10 0-40Mhz.
Even I am being aware of these changes, I am not able to read the status register with the op code 0x05, because I am not receiving any byte from the flash. As the pinout and the inherent circuits are the same ( Hold, CS and WP pins), as well the main OP codes, I think these FRAM models should be compatible and this CY15B004Q should be working plug-n-play without HW or FW modifications (at least to read the status register), am I right?
 
Is something missing from my analysis to explain this no-communication behavior of CY15B004Q model?
 
Datasheets:
 
Signal logs:
Red - clock;
Yellow - Hold;
Blue - MTRS;
Green - MRST
 
CS - is high before first clock signal starts and after second signal clock stops.
WP
WP - is always ON
RicardoALFCG_0-1648551812081.bmp

 

 
Thank you for your time and hope you can help me!
 
 
Best regards,
Ricardo Goncalves
0 Likes
3 Replies
PradiptaB_11
Moderator
Moderator
Moderator
500 replies posted 250 solutions authored 250 replies posted

Hi Ricardo,

Can you share us scope shots with SCK, SI,SO, and CS line. We need to see if the device is responding anything on the SO line after the opcode for reading SR is fed into the device. On first analysis if you are unable to read the SR then something might be wrong on the connection side (maybe some connection is loose or faulty). If the connections are all ok then we should see some output on the SO line. 

Thanks,

Pradipta.

0 Likes
RicardoALFCG
Level 1
Level 1
First reply posted First question asked Welcome!

Hello Pradipta,

Thank you for your answer. I dont think it is a matter of loose connections because I have several units with this F-RAMs with the same problem. I already removed this F-RAM from one device and solder a FM25V10 and everything is working fine. From my analysis:

-The application circuits are the same from both datasheets;

-The op commands for read the status register are the same;

- Dont think it is a loose connection because it is a industrial process and none of the units work;

When applying VDD, is there any measure I can make to verify if the flash is alive? I mean without expecting something on SO.

Here the screenshot with  SCK (Yellow), SI(Blue) ,SO (green) , and CS (Red) lines.

RicardoALFCG_0-1648664886818.png

 

Best regards, 

Ricardo Gonçalves

 

0 Likes

Hi,

Can you check for the tPU time you are using for CY15B004Q device. It should be a min of 1ms. For the FM25V10 this value is 250 us. Can you check this value being used by your software appliaction.

Thanks,

Pradipta.

0 Likes