C8051F340 Datasheet, PDF (144/282 Pages) List of Unclassifed Manufacturers – Full Speed USB Flash MCU Family

C8051F340/1/2/3/4/5/6/7
SFR Definition 14.6. CLKSEL: Clock Select
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W Reset Value
-
USBCLK
-
CLKSL
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0 SFR Address
0xA9
Bit 7:
Bits6–4:
Unused. Read = 0b; Write = don’t care.
USBCLK2–0: USB Clock Select
These bits select the clock supplied to USB0. When operating USB0 in full-speed mode, the
selected clock should be 48 MHz. When operating USB0 in low-speed mode, the selected
clock should be 6 MHz.
USBCLK
000
001
010
011
100
101
110
111
Selected Clock
4x Clock Multiplier
Internal Oscillator / 2
External Oscillator
External Oscillator / 2
External Oscillator / 3
External Oscillator / 4
RESERVED
RESERVED
Bit3: Unused. Read = 0b; Write = don’t care.
Bits2–0: CLKSL2–0: System Clock SelectThese bits select the system clock source.
CLKSL
000
Selected Clock
Internal Oscillator (as determined by the
IFCN bits in register OSCICN)
001
External Oscillator
010
4x Clock Multiplier / 2
011*
100
101-111
4x Clock Multiplier*
Low-Frequency Oscillator
RESERVED
*Note: This option is only available on 48 MHz devices
144
Rev. 0.5