C8051F530-IT Silicon Laboratories Inc, C8051F530-IT Datasheet - Page 142

• Manufacturer Part Number: C8051F530-IT
• Description: IC 8051 MCU 8K FLASH 20TSSOP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F53xr

Specifications of C8051F530-IT

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.25 V
• Data Converters: A/D 16x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 20-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: 336-1343

C8051F52x/F52xA/F53x/F53xA
14.3. System Clock Selection
The internal oscillator requires little start-up time and may be selected as the system clock immediately fol-
lowing the OSCICN write that enables the internal oscillator. External crystals and ceramic resonators typ-
ically require a start-up time before they are settled and ready for use. The Crystal Valid Flag (XTLVLD in
register OSCXCN) is set to 1 by hardware when the external oscillator is settled. To avoid reading a false
XTLVLD in crystal mode, the software should delay at least 1 ms between enabling the external
oscillator and checking XTLVLD. RC and C modes typically require no startup time.
The CLKSL bit in register CLKSEL selects which oscillator source is used as the system clock. CLKSL
must be set to 1 for the system clock to run from the external oscillator; however the external oscillator may
still clock certain peripherals (timers, PCA) when another oscillator is selected as the system clock. The
system clock may be switched on-the-fly between the internal oscillator and external oscillator, as long as
the selected clock source is enabled and has settled.
SFR Definition 14.5. CLKSEL: Clock Select
142
Bits7–6: Unused. Read = 00b; Write = don’t care.
Bits5–4: Reserved. Read = 00b; Must write 00b.
Bit3:
Bits2–1: Reserved. Read = 00b; Must write 00b.
Bit0:
Bit7
R
-
Unused. Read = 0b; Write = don’t care.
CLKSL: System Clock Select
0: Internal Oscillator (as determined by the IFCN bits in register OSCICN).
1: External Oscillator.
Bit6
R
-
Reserved Reserved
R/W
Bit5
R/W
Bit4
Rev. 1.3
Bit3
R
-
Reserved Reserved
R/W
Bit2
R/W
Bit1
SFR Address:
CLKSL
R/W
Bit0
00000000
Reset Value
0xA9