Low Voltage Detection
The function of Low Voltage Detection (LVD) is to inform systems and users the circumstance of present voltage. In other words, it keeps eyes on the voltage variations of a system to prevent an excessive low voltage, which may possibly result in a system failure or crash. Total of seven LVD options are available in GPCE4 - 2.4V, 2.6V, 2.8V, 3.0V, 3.2V, 3.4V, and 3.6V. In addition to that, a Low Voltage Reset (LVR) is also outfitted to generate a reset signal to keep system performing on the right track when its working voltage drops below the given LVD level.
Serial Peripheral Interface
Serial Peripheral Interface (SPI) is a synchronous data bus that offers separate lines for data and clock to keep two sides of talk in synchronous. The SPI controller built inside GPCE4 as standard enables synchronous serial communication with master and slave peripherals. In our design, there are two SPIs and each contains four signal lines shared with four of designated IOs: SPICS (IOB12), SPICK (IOB13), SDI (IOB14), and SDO (IOB15). One of SPIs is able to run an external program, meaning the system program can be upgraded from the SPI if necessary.