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DS1113F1
CS4399
4.1 Overview
The internal MCLK is used to generate serial port clocks. See
for supported LRCK combinations.
4.1.5
System Interrupts
The CS4399 includes an open-drain interrupt output (INT pin). Interrupt mask registers control whether an event
associated with an interrupt status/mask bit pair triggers the assertion of INT. All types of interrupts are described in
4.1.6
System Reset
The CS4399 offers two types of reset options:
• Asserting RESET. If RESET is asserted, all registers and all state machines are immediately set to their default
values/states. No operation can begin until RESET is deasserted. Before normal operation can begin, RESET must
be asserted at least once after the VP supply is first brought up.
• Power-on reset (POR). If the VD supply is lower than the POR threshold specified in
, the VD register
fields and the state machines are held in reset, setting them to their default values/states. The POR releases the
reset when the VD supply goes above the POR threshold. When the VD supply is turned on, the VL and VA supplies
must also be turned on at the same time.
4.1.7
Power Down
The CS4399 has a register byte to power down individual components on the chip. Before any change can be applied to
an individual component (except PLL), the block must be powered down first. For the PLL, changes can be applied after
PLL_START is cleared.
The PDN_HP bit is responsible for enabling or disabling the playback signal chain operation. All the necessary
components for playback operation need to be powered up and configured properly before PDN_HP is cleared. To disable
the playback signal chain, PDN_HP is set. PDN_HP needs to be set before making any changes to the playback signal
chain setup, except the following functions:
• Volume and mute related functions
• PCM filter settings (see
)
Before ASP, XSP, or DSDIF can safely power down, PDN_HP must be asserted, and PDN_DONE_INT must be present.
For XTAL or PLL used as the source of internal MCLK, PDN_HP needs to be set first and MCLK source needs to be
properly switched away before PDN_XTAL or PDN_PLL is set. If PLL output is only used as the source of CLKOUT, PDN_
PLL can be set without PDN_HP being asserted. If the steps described above are not followed, the CS4399 enters an
unresponsive state.
PDN_CLKOUT does not require PDN_HP to be set before it is asserted.
Recommended power-up and power-down sequences can be found in the
.