nRF52832 and state of I2c during system off

[scotts]

What are the guaranteed state of the IO lines (configured ax I2c) when in system off mode? Specifically I want another device to be on the bus acting as a master while nRF52832 is off. I’m trying to avoid having to add a buffer.

Thanks

[Stian Røed Hafskjold]

Hi, this is described in the TWIM chapter in the PS: infocenter.nordicsemi.com/.../twim.html

The PSEL.SCL and PSEL.SDA registers and their configurations are only used as long as the TWI master is enabled, and retained only as long as the device is in ON mode. When the peripheral is disabled, the pins will behave as regular GPIOs, and use the configuration in their respective OUT bit field and PIN_CNF[n] register. PSEL.SCL, PSEL.SDA must only be configured when the TWI master is disabled.

To secure correct signal levels on the pins used by the TWI master when the system is in OFF mode, and when the TWI master is disabled, these pins must be configured in the GPIO peripheral as described in Table 1.

So, configured correctly the GPIOs are acting as high impedance input pins in system OFF mode.