Help. Cannot write to PCA9558's EEPROM

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Ayman Bahouth

Mar 23, 2017, 4:52:07 AM3/23/17
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I have PCA9558 connected to I2C bus (i2c0, designware_i2c driver, 100KHz). I'm trying to write to it's EEPROM using i2c commands through U-Boot Terminal without any success.

The PCA9558 is the only device connected to i2c0, but when I 'i2c probe' command I get a message says "Valid chip addresses: " with empty list (the device address is 0x4E).

Dumping the EEPROM memory using the command "i2c md 0x4e 0x0300.2 100" prints out a list of "00".

Trying to write to the EEPROM using "i2c mw 0x4e 0x0100.2 0xCCBB 2" then dumping the memory again give me the same result, a series of "00".

I checked the clock and the data signals using a scope, and both seems to be fine. I can see the start condition, slave address, the command, the acknowledgements and the data at pins 0 and 1 are synchronized. The WP have a constant 0V. I tried everything in more than one PCB, all with the same behavior.

One more thing, I have an EEPROM connected to i2c1. Probing i2c1 returns the EEPROM address, and I can read/write to the EEPROM, so the driver is good.


Any advice when I can't write to the PCA9558 EEPROM? Why I can't see it's address when I probe the i2c? Am I using the correct commands to read/write to the EEPROM?


Appreciate your help,


Robert Nelson

Mar 23, 2017, 10:32:22 AM3/23/17
to Beagle Board,
I see you posted this exact same question to multiple forums. (nxp related)..

You "should" include what processor and what version of u-boot you are
using, otherwise you will NOT get any good answers.. (ps, it's not
BeagleBoard related, as we don't deal with the designware_i2c driver
in our products)

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Robert Nelson
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