C8051F509-IMR Silicon Labs, C8051F509-IMR Datasheet - Page 84

• Manufacturer Part Number: C8051F509-IMR
• Description: 8-bit Microcontrollers - MCU 50 MIPS 64 kB 4 kB SPI UART I2C
• Manufacturer: Silicon Labs

Specifications of C8051F509-IMR

• Rohs: yes
• Core: 8051
• Data Bus Width: 8 bit
• Processor Series: C8051

C8051F50x/F51x
10. Voltage Regulator (REG0)
C8051F50x/F51x devices include an on-chip low dropout voltage regulator (REG0). The input to REG0 at
the V
enabled, the output of REG0 appears on the V
power external devices. On reset, REG0 is enabled and can be disabled by software.
The Voltage regulator can generate an interrupt (if enabled by EREG0, EIE2.0) that is triggered whenever
the V
flag and the recommended procedure to use it is as follows:
1. Wait enough time to ensure the V
2. Enable the dropout interrupt (EREG0, EIE2.0) and select the proper priority (PREG0, EIP2.0)
3. If triggered, inside the interrupt disable it (clear EREG0, EIE2.0), execute all procedures necessary to
4. In the main application, now running in the safe mode, regularly checks the DROPOUT bit
The input (V
tor (4.7 µF + 0.1 µF) to ground as shown in Figure 10.1 below. This capacitor will eliminate power spikes
and provide any immediate power required by the microcontroller. The settling time associated with the
voltage regulator is shown in Table X.
If the internal voltage regulator is not used, the V
Figure 10.2.
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protect your application (put it in a safe mode and leave the interrupt now disabled.
(REG0CN.0). Once it is cleared by the regulator hardware the application can enable the interrupt
again (EREG0, EIE1.6) and return to the normal mode operation.
REGIN
REGIN
input voltage drops below the dropout threshold voltage. This dropout interrupt has no pending
pin can be as high as 5.25 V. The output can be selected by software to 2.1 V or 2.6 V. When
Figure 10.1. External Capacitors for Voltage Regulator Input/Output—
REGIN
) and output (V
REG0
V
DD
DD
) of the voltage regulator should both be bypassed with a large capaci-
4.7 µF
4.7 µF
REGIN
Regulator Enabled
input voltage is stable
DD
Rev. 1.2
pin, powers the microcontroller core, and can be used to
REGIN
.1 µF
.1 µF
input should be tied to V
V
V
DD
REGIN
DD
, as shown in