wm8400 Wolfson Microelectronics plc, wm8400 Datasheet - Page 156

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

WM8400
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CHIP RESET
HARDWARE RESET
SOFTWARE RESET
Table 103 Chip Reset and ID
R0 (00h)
Reset / ID
R1 (01h)
ID
REGISTER ADDRESS
A full hardware reset of the WM8400 can be implemented by powering down the device. Setting a
logic low level on NPDN (referenced to the HBVDD power domain) will initiate ‘soft shutdown’
sequence, where the CODEC and Power Management functions are disabled in a controlled manner,
avoiding audio pops and other undesirable effects. Following this reset, the device may be re-started
by asserting NPDN - see “Enabling the Device”.
CHIP RESET AND ID
The Device ID can be read back from Register 0. Writing to this register will reset the device.
Resetting the device will result in all DC-DC Converters and LDO Regulators being switched off and
will reset the NRST output to logic low level. Register read/wire operations are supported following a
software reset, but a complete re-starting of the device requires NPDN to be toggled.
Register 1 contains the Chip Revision ID
15:0
14:12
BIT
SW_RESET/CHIP_ID
[15:0]
(rr)
CHIP_REV [2:0]
(rr)
LABEL
6172h
000b
DEFAULT
Writing to this register resets all registers to their
default state.
Reading from this register will indicate Device ID
6172h.
Reading from this register will indicate the
Revision ID.
DESCRIPTION
PP, April 2009, Rev 3.0
Pre-Production
156