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Shail Shah
Shail Shah
Associate III
May 4, 2019
Question

Problem of External EEPROM (M95128-W) Reading Master Receive only 0xFF

  • May 4, 2019
  • 1 reply
  • 755 views

uc : STM32446

EEPROM : M95128-W

Interface : SPI

We are sending signal 0x06 (Write Enable) oxo5 (RDSR) and getting response from EEPROM (SPI Slave)0xFF instead of 0x2.

Any Data send via SPI we are receiving 0xFF. 

How to send and receive data to EEPROM With correct sequence?

How to know Slave sending data or Slave not active?

What is the possible reason to get 0xFF every sending of one byte.

Tried using different phase and polarity of signal and even put delay after sending one command.

This topic has been closed for replies.

1 reply

Pierre P.
Pierre P.
ST Employee
May 16, 2019

​Hello,

How to send and receive data to EEPROM With correct sequence?

Select & deselect the eeprom between each instructions ( Select ==> 0x06==> Deselect==> Select ==> 0x05 0x00 ==> Deselect)

How to know Slave sending data or Slave not active?

A deselect stops any transmission if salve active.

What is the possible reason to get 0xFF every sending of one byte

Eeprom not selected

please follow AC/DC characteristics ( max 20MHz and vcc range according to datasheet)

https://www.st.com/resource/en/datasheet/m95128-r.pdf

BR

EEPROM suPPort Team

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