C8051F39x/37x
13. Voltage Regulator
C8051F39x/37x devices include an internal regulator that regulates the internal core supply from a V
DD
supply of 1.8 to 3.6 V. The regulator has two power-saving modes built in to help reduce current consump-
tion in low-power applications. These modes are accessed through the REG0CN register.
13.1. Power Modes
Under default conditions, the internal regulator will remain on when the device enters STOP mode. This
allows any enabled reset source to generate a reset for the device and bring the device out of STOP mode.
For additional power savings, the STOPCF bit can be used to shut down the regulator and the internal
power network of the device when the part enters STOP mode. When STOPCF is set to 1, the RST pin
and a full power cycle of the device are the only methods of generating a reset.
SFR Definition 13.1. REG0CN: Voltage Regulator Control
Bit
7
6
5
4
3
STOPCF
R/W
2
1
0
Name
Type
Reset
R/W
R/W
0
0
0
0
0
0
0
0
SFR Address = 0xC9; SFR Page = All Pages
Bit
7:4
3
Name
Function
Reserved
STOPCF
Must Write 0000b.
Stop Mode Configuration.
This bit configures the regulator’s behavior when the device enters
STOP mode.
0: Regulator is still active in STOP mode. Any enabled reset
source will reset the device.
1: Regulator is shut down in STOP mode. Only the RST pin or
power cycle can reset the device.
2:0
Reserved
Must Write 000b.
Preliminary Rev. 0.71
73
SILICON [ SILICON ]
