C8051F330-GMR Datasheet, PDF (21/210 Pages) Silicon Laboratories – Mixed-Signal ISP Flash MCU

C8051F330/1/2/3/4/5
1.1.3. Additional Features
The C8051F330/1/2/3/4/5 SoC family includes several key enhancements to the CIP-51 core and periph-
erals to improve performance and ease of use in end applications.
The extended interrupt handler provides 14 interrupt sources into the CIP-51 (as opposed to 7 for the stan-
dard 8051), allowing numerous analog and digital peripherals to interrupt the controller. An interrupt driven
system requires less intervention by the MCU, giving it more effective throughput. The extra interrupt
sources are very useful when building multi-tasking, real-time systems.
Eight reset sources are available: power-on reset circuitry (POR), an on-chip V_DD monitor (forces reset
when power supply voltage drops below V_RST as given in Table 10.1 on page 102), a Watchdog Timer, a
Missing Clock Detector, a voltage level detection from Comparator0, a forced software reset, an external
reset pin, and an illegal Flash access protection circuit. Each reset source except for the POR, Reset Input
Pin, or Flash error may be disabled by the user in software. The WDT may be permanently enabled in soft-
ware after a power-on reset during MCU initialization.
The internal oscillator factory calibrated to 24.5 MHz ±2%. This internal oscillator period may be user pro-
grammed in ~0.5% increments. An additional low-frequency oscillator is also available which facilitates
low-power operation. An external oscillator drive circuit is included, allowing an external crystal, ceramic
resonator, capacitor, RC, or CMOS clock source to generate the system clock. If desired, the system clock
source may be switched on-the-fly between both internal and external oscillator circuits. An external oscil-
lator can also be extremely useful in low power applications, allowing the MCU to run from a slow (power
saving) source, while periodically switching to the fast (up to 25 MHz) internal oscillator as needed.
Px.x
Px.x
XTAL1
XTAL2
Low
Frequency
Oscillator
Internal
Oscillator
External
Oscillator
Drive
Comparator 0
+
-
C0RSEF
VDD
Supply
Monitor
+
-
Enable
Power On
Reset
'0'
(wired-OR)
Missing
Clock
Detector
(one-
shot)
EN
PCA
WDT
EN
Reset
Funnel
(Software Reset)
SWRSF
Errant
FLASH
Operation
System
Clock
Clock Select
CIP-51
Microcontroller ^{System Reset}
Core
Extended Interrupt
Handler
Figure 1.8. On-Chip Clock and Reset
/RST
Rev. 1.7
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