SPRUIM6A October 2018 – November 2020
ISSUE: The I2C IO Expanders (U110 and U7) provides additional control signals for the EVM. The I2C component does not include a reset input and is only reset to the default values when a power cycle is applied. Thus, if a PORz or warm reset occurs after the power is applied, the output values programmed into the IO expanders will not change. While most values can be reprogrammed by software after a reset is applied as a work-around, the expander does include the GPIO_eMMC_RSTn, GPIO_OSPI_RSTn, MMC1_SD_EN, and the GPIO_SPI0_RSTn signals. These signals hold the associated interfaces in a reset state if set to an active state. If a GPIO reset signal is applied to an interface that is used as a boot device, the boot will not succeed.
SOLUTION: In future versions of the board, an I2C IO expander with a reset input will be substituted for these devices.
WORKAROUND: There is no complete work-around for this issue. The customer should avoid leaving any boot interface in reset for extended periods of time. Even if the reset to this interface is pulsed active, there is a possibility of a reset occurring while the peripheral reset is active, preventing the board from booting. Boot software should reinitialize the I2C IO Expanders.