SNAS811 July 2020 – May CDCE6214
As the programming interface can be intentionally deactivated using the EEPROM, an accidental disabling of the I2C blocks further access to the device. The serial interface can be forced using the fall-back mode. To enter this mode, the user leaves pin 4 and pin 23 floating while the supply voltage is applied to VDDREF. In this mode, EEPROM Read at power up is bypassed and device boots in default mode. In this mode, pin 11 is pre-configured as an input and pin 20 is configured as an output. After powering up in fall-back mode, the device can be re-programmed through serial interface and be re-configured for normal operation. EEPROM can also be re-programmed. The PLL would not be auto-calibrated, however, and the I2C interface would be active. This mode would allow the user to fully configure the device before re-locking the PLL.