3V SPI/I2C voltage translation

Konrad.Z · Posted at 1/31/2018 15:59:12

I want to connect my MCU that run on 3.3V with your board via SPI and I2C, but FireFly voltage level on these buses is 3V. Will I need voltage translation or will it be on spec with FireFly ?

leung先森 · Posted at 1/31/2018 17:00:05

Basiclly, 3.3v is the same as 3v .
But if your MCU is serious about voltage controled, just try apply 3v to your MCU.
I trust your MCU have its Float voltage.

Konrad.Z · Posted at 1/31/2018 19:46:12

Ok, thanks.

big_whit · Posted at 2/5/2018 03:13:58

Does anyone actually knows if the RK3399 VDDIOs bank @3.0V are Voltage tolerant to VDD+0.3V . Trying to find the information in the RK3399 datasheet but can't find anything.

As per the RK3399 carrier board schematic - the UART2DBG_RX net it directly tied to a 3.3V pullup and the IO bank is set to 3.0V. Any long term issue with this ?

leung先森 · Posted at 2/5/2018 09:35:57

big_whit Posted at 2/5/2018 03:13
Does anyone actually knows if the RK3399 VDDIOs bank @3.0V are Voltage tolerant to VDD+0.3V . Trying ...

u can try to set up the group gpio of the UART2DBG_RX from the hardware datasheet.
It is controled by pmu.