FM24VXX Not Acknowledging

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

cross mob
SensibleChuckle
Level 1
Level 1
First question asked Welcome!

Hi all,

I am trying to interface a FM24V05 to an STM32H723 on a custom PCB, but for some reason it will not acknowledge to any write/read requests in the addressing phase. I have confirmed the address is correct and it will not reply to any of the reserved slave ID's either. I have swapped out the chip for an FM24V10 as well as other chips from a different batch. Further, I have a CY8CKIT-044 and swapped the FM24V05 onto it and found it was successfully addressed by Bridge Control. 

Attached is a image of a signal analyser readout of the transaction running at 100kHz (I have tried using lower frequencies) and probed directly on the SO8 pins to rule out bad solder joints. A 3.3V supply is provided to the chip with a 0.1uF cap right next to it and was observed with an oscilloscope showing no obvious power problems between VCC and GND.

There are other devices on the bus which are all successfully talked to (I disconnected them to rule them out), with 2k7 resistors pulling the I2C lines high.

I took a signal analyser capture of the chip talking on the CY8CKIT-044 and saw no real differences and compared the schematic/PCB files and again saw no real concerns.

This has stumped me for quite a while so any help would be great!

Cheers,

Luke

fm24V0.PNG

0 Likes
1 Solution
Ritwick_S
Moderator
Moderator
Moderator
100 solutions authored 25 likes received 250 sign-ins

Hi @SensibleChuckle,

 

> Could you please share the schematic of your custom PCB with us that involves our FRAM?

> Please share the power-up and power-down waveforms with us.

Also, when you are using CY8CKIT-044 kit, you are able to successfully read and write, correct?

 

Thanks,

Ritwick

View solution in original post

0 Likes
1 Reply
Ritwick_S
Moderator
Moderator
Moderator
100 solutions authored 25 likes received 250 sign-ins

Hi @SensibleChuckle,

 

> Could you please share the schematic of your custom PCB with us that involves our FRAM?

> Please share the power-up and power-down waveforms with us.

Also, when you are using CY8CKIT-044 kit, you are able to successfully read and write, correct?

 

Thanks,

Ritwick

0 Likes