C8051F412-GQ Silicon Laboratories Inc, C8051F412-GQ Datasheet - Page 174

• Manufacturer Part Number: C8051F412-GQ
• Description: IC 8051 MCU 16K FLASH 32LQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F41xr

Specifications of C8051F412-GQ

• Program Memory Type: FLASH
• Program Memory Size: 16KB (16K x 8)
• Package / Case: 32-LQFP
• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 50MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 24
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.25 V
• Data Converters: A/D 20x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: C8051F4x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 2.25 KB
• Interface Type: I2C/SMBus/SPI/UART
• Maximum Clock Frequency: 50 MHz
• Number Of Programmable I/os: 24
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051F410DK
• Minimum Operating Temperature: - 40 C
• On-chip Dac: 2-ch x 12-bit
• No. Of I/o's: 24
• Ram Memory Size: 2368Byte
• Cpu Speed: 50MHz
• No. Of Timers: 4
• Rohs Compliant: Yes
• Package: 32LQFP
• Device Core: 8051
• Family Name: C8051F41x
• Maximum Speed: 50 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 770-1006 - ISP 4PORT FOR SILABS C8051F MCU336-1453 - ADAPTER PROGRAM TOOLSTICK F410336-1317 - KIT EVAL FOR C8051F411336-1314 - KIT DEV FOR C8051F41X
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1310

C8051F410/1/2/3
19.4. 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 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[1:0] bits in register CLKSEL select which oscillator source is used as the system clock.
CLKSL[1:0] must be set to 01b for the system clock to run from the external oscillator; however the exter-
nal 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, external oscilla-
tor, smaRTClock oscillator, and Clock Multiplier, as long as the selected clock source is enabled and has
settled.
174
Bits7–6: Unused. Read = 00b; Write = don’t care.
Bits5–4: CLKDIV1–0: Output /SYSCLK Divide Value
Bit3:
Bit2:
Bits1–0: CLKSL1–0: System Clock Select
Bit7
R
-
These bits can be used to pre-divide the /SYSCLK output before it is sent to a port pin
through the Crossbar.
00: Output will be SYSCLK.
01: Output will be SYSCLK/2.
10: Output will be SYSCLK/4.
11: Output will be SYSCLK/8.
Unused. Read = 0b; Write = don’t care.
Reserved. Read = 0b; Must write 0b.
These bits select the system clock source.
Bit6
R
-
CLKSL
00
01
10
11
SFR Definition 19.5. CLKSEL: Clock Select
R/W
Bit5
CLKDIV
R/W
Bit4
Internal Oscillator (as determined by the
IFCN bits in register OSCICN)
Rev. 1.1
smaRTClock Oscillator
Bit3
External Oscillator
R
-
Selected Clock
Clock Multiplier
Reserved
R/W
Bit2
R/W
Bit1
CLKSL
SFR Address:
R/W
Bit0
0xA9
00000000
Reset Value