Uboot- I2c writing EEPROM - not taken

Embedded Linux Discussions
1

Hi Robert,

I am using U-boot read EEPROM:
=> i2c md 0x50 0x0.2 0x30
0000: aa 55 33 ee 41 33 33 35 42 4e 4c 54 42 57 41 35 .U3.A335BNLTBWA5
0010: 31 38 34 33 42 42 57 47 30 30 31 32 ff ff ff ff 1843BBWG0012…
0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff …

Then I write to address 0x0020 using the following command:
=> i2c mw 0x50 0x20.2 32 1
The command seems executed without error (If I sent a wrong command, it shows help messages). So I assume the above write command was ok.
But I read the EEPROM, using the first command, the addess 0x0020 is still 0xFF.

In the BBB reference manu/schematic, (Section 5.3.2 32KB EEPROM ), it doesn’t state any write-protection pin. Section 8.0 there is a WP pin, but that is for each cape.
Is it because of EEPROM write-protected or something else is wrong?

Thank You,
David

2

Hi @dzhou, based on the eeprom, this looks like a BeagleBone Black Wireless, is that correct?

For the BeagleBone Black Wireless, the “board” eeprom write protected is located on TP1. Just GND it, to be able to write any data:

BBBW_eeprom
BBBW_eeprom379×560 291 KB

Regards,

3

Very cool. Thank you.
David

4

Hi Robert,

Is EEPROM write-enable (or protection ) pin on the TP1 programmable through c code? Or it has to be jumped to ground with a jumper?

Thank you,
David

5

Hi @dzhou,

On the BBBW, the TP1 is not accessible to any of the pins on the OSD3358.

The updated OSD3358 (used on the PocketBeagle) with a built-in i2c eeprom has the Write-Protect pin connected to a gpio pin.

Regards,