M95320 Device Information Page not returning

[dman]

Posted on June 28, 2018 at 11:54

Hi,

I am using the M95320 EEPROM and sending RDID instruction to read the Device Identification page however the device is responding with 0xFF for all 32 bytes on the MISO line. The 2 byte address I am sending is 0x00 0x00.

The EEPROM IC has:

• Vcc and S with a 102k Resistor
• HOLD is HIGH
• W is HIGH

I also send theRDSR instruction to read the status byte and the IC is responding with 0x00 on the MISO line.

I am very confused as it seems that I can read the Status Byte, but not the Device Information.

Any advice would be greatly appreciated.

edit:

I can confirm now that I can read and write Memory data via the READ and WRITE commands. I can read and write the Status byte, however the Device Identification still cannot be read. Here is the sample of the SPI traces.

As you can see the Red (MOSI) line is always high. I did double check and there is no Write in progress.

#spi-communication #eeprom-memory #m95320 #spi

Note: this post was migrated and contained many threaded conversations, some content may be missing.

[dman]

Posted on July 02, 2018 at 09:18

Seriously? Anyone?

[Nilesh Vora]

Posted on July 03, 2018 at 14:13

At least you can read the status register, I am not able to read it either. Can you please share your initialization sequence?

[dman]

Posted on July 04, 2018 at 10:29

Hi Nilesh,

I used this guide - 

https://www.st.com/resource/en/datasheet/m95320-a125.pdf

 

I do not have an initialisation procedure for the device but these are the things that I have done:

• HOLD pin is bridged with the Vcc to keep it high.
• The S (chip select) pin is bridged with the Vcc via 102k Ohm resistor ( I do not have 100k) - see '5.1.2 Power-up conditions'
• Make sure that your SPI word is 8 bits.

Also remember that the Vcc level relates to the SPI bus speed.

• High speed clock frequency
  • 20 MHz for VCC ≥ 4.5 V
  • 10 MHz for VCC ≥ 2.5 V
  • 5 MHz for VCC ≥ 1.7 V

Instead, I think you should submit your initialisation or the SPI traces.

[Pierre P.]

Posted on July 06, 2018 at 10:47

Hi,

Please make sure of the instruction format ( 1000 0011  + 2 bytes address ) for RDID.

Warning A10 bit address must be '0'. in case of doubt, send 2 address bytes with = 0x00

Do you have a virgin part or not ? in case of not virgin part, may be 0xFF is the right value located at this area .

ps: no Write in progress during a read.