
CHAPTER 10 AIU (AUDIO INTERFACE UNIT)
User’s Manual U14579EJ2V0UM
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10.3 Operation Sequence
10.3.1 Output (Speaker)
(1) When using DMA transfer
<1> Set D/A conversion rate (SCNVR(2:0) area in SCNVRREG register = any value)
<2> Set output data area to DMAAU
<3> DMA enable in DCU
<4> Set D/A converter’s DAAVREF to ON (DAENAIU bit of SCNTREG register = 1)
<5> Wait for DAAVREF resistor stabilization time (about 5
s) (use the RTC counter)
Even if speaker power is set to ON and speaker operation is enabled (AIUSEN bit = 1) without waiting
for DAAVREF resistor stabilization time, speaker output starts after the period calculated with the formula
below.
5 + 1/conversion rate (44.1, 22.05, 11.025, or 8 ksps) (
s)
In this case, however, a noise may occur when speaker power is set to ON.
<6> Set speaker power to ON via GPIO
<7> Speaker operation enable (AIUSEN bit of SEQREG register = 1)
When the speaker operation is enabled, the following internal operations occur.
1. DMA request
2. Receive acknowledge and DMA data from DMA
DVALIDREG register’s SDMAV bit = SODATV bit = 1
3. Output 10-bit data (SODAT(9:0) area in SODATREG register) to D/A converter
SODATV bit = 0, SDMAV bit = 1
Send SDMADATREG register data to SODATREG register.
SODATV bit = 1, SDMAV bit = 0
4. Output DMA request and store the data after the next into SDMADATREG register.
SODATV bit = 1, SDMAV bit = 1
5. Refresh data at each conversion timing interval
Becomes SIDLEINTR bit = 1 when DMA is slow and SODATV bit = 0 during conversion timing
interval, and (mute) interrupt occurs
6. DMA page boundary interrupt occurs at page boundary
Clear the page interrupt request to continue output.
<8> Speaker operation disable (AIUSEN bit of SEQREG register = 0)
<9> Set speaker power to OFF via GPIO
<10> Set D/A converter’s DAAVREF to OFF (DAENAIU bit of SCNTREG register = 0)
<11> DMA disable in DCU