WM8321 Datasheet, PDF (38/253 Pages) Wolfson Microelectronics plc – Processor Power Management Subsystem

WM8321
ADDRESS
R16401
(4011h)
Interrupt Status
1
R16409
(4019h)
Interrupt Status
1 Mask
BIT
LABEL
12 ON_PIN_CINT
12 IM_ON_PIN_CINT
Table 6 ON Pin Interrupt
Production Data
DESCRIPTION
ON pin interrupt.
(Rising and Falling Edge triggered)
Note: Cleared when a ‘1’ is written.
Interrupt mask.
0 = Do not mask interrupt.
1 = Mask interrupt.
Default value is 1 (masked)
11.7 RESET PIN FUNCTION
The R¯¯E¯S¯E¯T¯ pin is an active low input/output which is used to command Hardware Resets in the
WM8321 and in other connected devices. The pin is an open-drain type, with integrated pull-up; it can
be driven low by external sources or by the WM8321 itself.
The WM8321 drives the R¯¯E¯S¯E¯T¯ pin low in the OFF state. The output status of the R¯¯E¯S¯E¯T¯ pin in
SLEEP is configurable; this is determined by the RST_SLPENA register bit as defined in Table 7.
The WM8321 clears the R¯¯E¯S¯E¯T¯ pin following the transition to ON. On completion of the state
transition, the R¯¯E¯S¯E¯T¯ pin is held low for a further delay time period, extending the R¯¯E¯S¯E¯T¯ low
duration. The R¯¯E¯S¯E¯T¯ delay period is set by the RST_DUR register bit. See Figure 6 for further
details.
The WM8321 detects a Hardware Reset request whenever the R¯¯E¯S¯E¯T¯ pin is driven low by an
external source. In this event, the WM8321 resets the internal control registers (excluding the RTC)
and initiates a start-up sequence. See Section 24.
It is possible to mask the R¯¯E¯S¯E¯T¯ pin input in the SLEEP state by setting the RST_SLP_MSK register
bit. In SLEEP mode, if RST_SLP_MSK is set, the WM8321 will take no action if the R¯¯E¯S¯E¯T¯ pin is
pulled low.
Note that the R¯¯E¯S¯E¯T¯ pin control registers are locked by the WM8321 User Key. These registers can
only be changed by writing the appropriate code to the Security register, as described in Section 12.4.
ADDRESS
R16390 (4006h)
Reset Control
BIT
LABEL
5 RST_SLP_MSK
4 RST_SLPENA
1:0 RST_DUR
Table 7 RESET Pin Control Registers
DEFAULT
1
1
11
DESCRIPTION
Masks the R¯¯E¯S¯E¯T¯ pin input in
SLEEP mode
0 = External R¯¯E¯S¯E¯T¯ active in SLEEP
1 = External R¯¯E¯S¯E¯T¯ masked in
SLEEP
Protected by user key
Sets the output status of R¯¯E¯S¯E¯T¯ pin
in SLEEP
0 = R¯¯E¯S¯E¯T¯ high (not asserted)
1 = R¯¯E¯S¯E¯T¯ low (asserted)
Protected by user key
Delay period for releasing R¯¯E¯S¯E¯T¯
after ON or WAKE sequence
00 = 3ms
01 = 11ms
10 = 51ms
11 = 101ms
Protected by user key
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PD, February 2012, Rev 4.0
38