STM32U5G9J-DK1 signal levels

[Kelly3]

I am designing interface board  similar to MB1835 for our touchscreen to work with MB1829.  STM32U5G9NJH6Q power supply VDD, VDDA, VDDIO and VDDUSB are all supplied with 1.8V. Thus, STM32U5G9NJH6Q GPIO is compatible with 1.8V signals. Touch Screen connects to MB1835 also has signal levels of 1.8V. i.e.  I2C_SCL,  I2C_SDA, Screen_int, screen_resetn are of signal level 1.8V. Yet, all these signals are designed to use level shifter on MB1835. May I know why?  And for our customized interface board, may touchscreen with 1.8V  signals interface with STM32U5G9NJH6Q GPIO directly? 

Thank you.

Kelly

[Mike_ST · Accepted solution]

Hello,

A level shifter is needed on MB1835, because the Sitronix touch panel controller signals need to be between 2.7V and 3.6V (on CN2).

If you have an 1.8V touchscreen controller, it should work with an mcu with 1.8V I/Os.