Cypress S6J3200 Series, Manual

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CHAPTER 34:Sound System Configuration
S6J3200 Series Hardware Manual Document Number: 002-04852 Rev. *G 1305
4.
Configuration and limitation of each module
This section shows configurations and limitations about each module interface in the sound system.
4.1.
Interface between SMIX and DAC
Output modules including DAC are connected to SMIX by a dedicated bus interface. On this interface, the
sound source transfer between SMIX and DAC is triggered by a data request from DMA interface of DAC.
DAC has two initialization procedures (refer to the chapter of the DAC for the details). One is "DMA
Interface Unused", and the other is "DMA Interface Used". DAC must be initialized by the procedure of
"DMA Interface used", because the sound source is transferred from SMIX to DAC by using DMA
interface.
Because it is impossible to transfer the sound source from DMAC to DAC directly, the sound source
needs to be transferred to DAC via SMIX. Therefore, the initialization of the SMIX is necessary even if it is
not necessary to do the mixing of the sound source. If the sound source is not mixing, only 1 PMIS input
channel (any number of channels can be used) of SMIX should be enabled.
4.1.1.
Configuration
The address of DAC must be set to Output destination address of SMIX (MACRO of MXOCTRL register).
The actual setting value is the following.
−
MACRO of MXOCTRL register : 0x1
Number of transfers to output destination of SMIX (DATATN of MXOCTRL register) must be same as
FIFO empty threshold of DAC (FEST of DACTRL register).
4.1.2.
Limitation
Because the sound sources are transferred surely from SMIX to DAC, the following registers must not be
changed during the sound source translation.
Even if SMIX is disabled by MXCH register, the data transfer from SMIX to DAC is not stopped
immediately. Therefore, the following register must not be changed after setting it at the initialization.
−
DACTRL
−
MXOCTRL
4.2.
Interface between SMIX and PCM-PWM
Output modules including PCM-PWM are connected to SMIX by a dedicated bus interface. On this
interface, the sound source transfer between SMIX and PCM-PWM is triggered by a data request from
DMA interface of PCM-PWM.
PCM-PWM supports two type data transfers. One is "DMA mode", and the other is "CPU mode".
PCM-PWM must be set to "DMA mode", because the sound source is transferred from SMIX to
PCM-PWM by using DMA interface.
Because it is impossible to transfer the sound source from DMAC to PCM-PWM directly, the sound
source needs to be transferred to PCM-PWM via SMIX. Therefore, the initialization of the SMIX is
necessary even if it is not necessary to do the mixing of the sound source. If the sound source is not
mixing, only 1 PMIS input channel (any number of channels can be used) of SMIX should be enabled.