wm8400 Wolfson Microelectronics plc, wm8400 Datasheet - Page 138

• Manufacturer Part Number: wm8400
• Description: Wolfson Audioplustm Hi-fi Audio Codec And Power Management Unit For Mobile Multimedia
• Manufacturer: Wolfson Microelectronics plc

WM8400
w
The DC-DC converters, LDO1 and LDO2 can also be enabled by asserting a logic high level on the
associated hardware pins. These logic inputs are referenced to HBVDD. A logic high on these pins
takes precedence over the corresponding software control.
The hardware enable pins may be connected to the power sequencing outputs PSEQ1, PSEQ2,
PSEQ3, PSEQ4 or may be driven by another device. These pins should not be left floating
(unconnected); the logic state of these inputs is undefined if these pins are floating.
Table 82 DC-DC Converter and LDO Regulator Hardware Enable
LDO FUNCTION SELECT
To provide maximum flexibility, the LDOs can be configured to operate as current-limited switches
instead of as regulators. This is achieved by writing to the register bits defined below.
Table 83 LDO Function Select
R65 (41h)
R66 (42h)
R67 (43h)
R68 (44h)
DC1EN
DC2EN
LDO1EN
LDO2EN
REGISTER
ADDRESS
PIN NAME
BIT
14
14
14
14
DC1 Hardware enable
0 = Disable (software control)
1 = Enable
DC2 Hardware enable
0 = Disable (software control)
1 = Enable
LDO1 Hardware enable
0 = Disable (software control)
1 = Enable
LDO2 Hardware enable
0 = Disable (software control)
1 = Enable
LDO1_SWI
LDO2_SWI
LDO3_SWI
LDO4_SWI
LABEL
FUNCTION
DEFAULT
0b
0b
0b
0b
LDO1 function select
0 = LDO Regulator
1 = Current Limited switch
LDO2 Software enable
0 = LDO Regulator
1 = Current Limited switch
LDO3 Software enable
0 = LDO Regulator
1 = Current Limited switch
LDO4 Software enable
0 = LDO Regulator
1 = Current Limited switch
DESCRIPTION
PP, April 2009, Rev 3.0
Pre-Production
138