C8051F321-GMR Datasheet, PDF (70/250 Pages) Silicon Laboratories – Full Speed USB, 16 k ISP FLASH MCU Family

C8051F320/1
C8051F320/1
VBUS
From 5V
Power Net
To 3V
Power Net
REGIN
VDD
VBUS Sense
5V In
Voltage Regulator (REG0)
3V Out
Device
Power Net
Figure 8.5. REG0 Configuration: No USB Connection
SFR Definition 8.1. REG0CN: Voltage Regulator Control
R/W
REGDIS
Bit7
R
VBSTAT
Bit6
R/W
VBPOL
Bit5
R/W
R/W
R/W
R/W
R/W
Reset Value
REGMOD Reserved Reserved Reserved Reserved 00000000
Bit4
Bit3
Bit2
Bit1
Bit0 SFR Address:
0xC9
Bit7:
Bit6:
Bit5:
Bit4:
Bits3–0:
REGDIS: Voltage Regulator Disable.
0: Voltage Regulator Enabled.
1: Voltage Regulator Disabled.
VBSTAT: VBUS Signal Status.
0: VBUS signal currently absent (device not attached to USB network).
1: VBUS signal currently present (device attached to USB network).
VBPOL: VBUS Interrupt Polarity Select.
This bit selects the VBUS interrupt polarity.
0: VBUS interrupt active when VBUS is low.
1: VBUS interrupt active when VBUS is high.
REGMOD: Voltage Regulator Mode Select.
This bit selects the Voltage Regulator mode. When REGMOD is set to ‘1’, the voltage regu-
lator operates in low power (suspend) mode.
0: USB0 Voltage Regulator in normal mode.
1: USB0 Voltage Regulator in low power mode.
Reserved. Read = 0000b. Must Write = 0000b.
70
Rev. 1.4