1.6. Programmable Comparator
C8051F52x/F52xA/F53x/F53xA devices include a software-configurable voltage comparator with an input
multiplexer. The comparator offers programmable response time and hysteresis and an output that is
optionally available at the Port pins: a synchronous “latched” output (CP0). The comparator interrupt may
be generated on rising, falling, or both edges. When in IDLE or SUSPEND mode, these interrupts may be
used as a “wake-up” source for the processor. The Comparator may also be configured as a reset source.
A block diagram of the comparator is shown in Figure 1.8.
D SET Q
D SET Q
Figure 1.8. Comparator Block Diagram
1.7. Voltage Regulator
C8051F52x/F52xA/F53x/F53xA devices include an on-chip low dropout voltage regulator (REG0). The
input to REG0 at the VREGIN pin can be as high as 5.25 V. The output can be selected by software to 2.1 or
2.6 V. When enabled, the output of REG0 powers the device and drives the VDD pin. The voltage regulator
can be used to power external devices connected to VDD.
1.8. Serial Port
The C8051F52x/F52xA/F53x/F53xA family includes a full-duplex UART with enhanced baud rate configu-
ration, and an Enhanced SPI interface. Each of the serial buses is fully implemented in hardware and
makes extensive use of the CIP-51's interrupts, thus requiring very little CPU intervention.