[196] I2S: PSEL acquires GPIOs regardless of ENABLE

This anomaly applies to IC Rev. Engineering A, build codes QIAA-AA0.

Symptoms

I2S controls GPIO even when I2S is not enabled.

Conditions

When using I2S->PSEL to configure GPIO.

Consequences

GPIO selected for I2S cannot be used for any other peripheral.

Workaround

Do not rely on the pins selected in I2S->PSEL registers being free when I2S->ENABLE is set to DISABLE.

Only set the CONNECT bit in the I2S->PSEL registers to CONNECTED immediately before enabling I2S. When disabling I2S, set the CONNECT bit in the I2S->PSEL registers to DISCONNECTED.