# I2C Mutiplexer on WP7702 custom board **URL:** \ **Category:** Uncategorized\ **Created:** [March 22, 2022, 3:29pm UTC](https://mangoh.discourse.group/t/i2c-mutiplexer-on-wp7702-custom-board/9887 "2022-03-22T15:29:29Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![gianmariaiaculo](https://avatars.discourse-cdn.com/v4/letter/g/e19adc/32.png) [@gianmariaiaculo](https://mangoh.discourse.group/u/gianmariaiaculo)\ **Post date:** [March 22, 2022, 3:29pm UTC](https://mangoh.discourse.group/t/i2c-mutiplexer-on-wp7702-custom-board/9887/1 "2022-03-22T15:29:29Z")
Hello, dont know if this is the right forum at my point of work… We realized a custom board (prototype) starting from mangoh open hardware, so this is very close to the original product. On mangoh i see that i2c is multiplexed during boot and i have this devices under sys/class/i2c-adapter# i2c-4 i2c-5 i2c-6 i2c-7 i2c-8 On our board this multiplexing is not executed (DMESG) so I miss BMI160. I used same firmware (legato-19.11.5.cwe, WP77xx\_Release14.1\_GENERIC\_GCF\_PTCRB.spk and yellow.wp77xx.update), so I’m sure the software part is ok… at least I hope… But on custom board something is missing… no accel first. Maybe the software makes some choices asking system what board it’s running on? … in this case not finding a Yellow … it stops loading parts of drivers it need. Again, we used same schemas… so our hardware is so near to yellow. Regards, Gianmaria ---
**Author:** ![gianmariaiaculo](https://avatars.discourse-cdn.com/v4/letter/g/e19adc/32.png) [@gianmariaiaculo](https://mangoh.discourse.group/u/gianmariaiaculo)\ **Post date:** [March 22, 2022, 3:41pm UTC](https://mangoh.discourse.group/t/i2c-mutiplexer-on-wp7702-custom-board/9887/2 "2022-03-22T15:41:18Z")
errata corrige: our engeenering removed the multiplexer (physically). Now i have to bypass it if i want to talk with bmi160… any hint appreciated. Regads Gian