ATmega808/809/1608/1609 Errata and Clarification

SPI SS Pin is Connected to Pin Even if SPI is Configured to Have No Port Connection

The SPIn SS pin is connected even if NONE is selected in the SPIn field in PORTMUX.TWISPIROUTE. If SPIn is operating in Host mode and the SS pin goes low, or input is disabled, the SPIn will exit Host mode.

Work around

Write the SSD bit in SPIn.CTRLB to ‘1’ to ignore the SS signal.

Affected Silicon Revisions

Rev. A
X
Parent topic: PORTMUX