21 HW Processor (HWP) and Sound Output
S1C31D50/D51 TECHNICAL MANUAL
Seiko Epson Corporation
21-11
(Rev. 2.00)
When the volume returns back to the original level, a smoothing (fade-in) process for the playback output
signal is carried out to suppress the occurrence of noise due to a sudden rise of the signal.
Command execution
(Release Mute/Pause command)
Time
Smoothing process
Sound level
Figure 21.4.1.4 Smoothing Process when Playback Output is Resumed
When sound data ends in mute state
End of sound data automatically stops the muted playback output and the sound play function transits to sp_
state_idle state. If the HWPINTF.HWP0IF bit is set to 1 (occurrence of state transition) before releasing the
mute state, read the STATE_
n
.STATE[15:0] bits and check to see if they are set to 0x0001 (sp_state_idle).
Pause
Pause control
During playback, it can be paused with the procedure shown below.
1. Confirm that the STATE_
n
.STATE[15:0] bits = 0x0002 (sp_state_play).
2. Confirm that the STATUS.READY bit = 1.
(Command acceptable)
3. Set the COMMAND_
n
.COMMAND[7:0] bits to 0x04 or 0x05.* (Select Pause command)
4. Write 1 to the HWPCMDTRG.HWP0TRG bit.
(Trigger to issue command)
5. Wait until the HWPINTF.HWP0IF bit is set to 1 (interrupt).
(Occurrence of state transition)
The HWP pauses the playback output from this point.
6. Confirm that the STATE_
n
.STATE[15:0] bits = 0x0003 (sp_state_pause) as necessary.
7. Write 0 to the HWPINTF.HWP0IF bit.
(Clear interrupt flag)
*
Two pause commands are available. Setting the COMMAND_
n
.COMMAND[7:0] bits to 0x04 selects
the Pause Immediately command; setting to 0x05 selects the Pause after Current Phrase command.
Pause Immediately command
When this command is issued by the trigger bit, the playback output is paused immediately. At this
time, a smoothing (fade-out) process for the playback output signal is carried out to suppress the occur-
rence of noise. (See Figure 21.4.1.2.)
Pause after Current Phrase command
The playback output is paused after ending the phrase that is being output when the command is issued.
(See Figure 21.4.1.3.)
Pause release
The pause state can be released with the procedure shown below.
1. Confirm that the STATE_
n
.STATE[15:0] bits = 0x0003 (sp_state_pause).
2. Confirm that the STATUS.READY bit = 1.
(Command acceptable)
3. Set the COMMAND_
n
.COMMAND[7:0] bits to 0x06.
(Select Release Pause command)
4. Write 1 to the HWPCMDTRG.HWP0TRG bit.
(Trigger to issue command)
5. Wait until the HWPINTF.HWP0IF bit is set to 1 (interrupt).
(Occurrence of state transition)
The HWP resumes playback output from this point.
6. Confirm that the STATE_
n
.STATE[15:0] bits = 0x0002 (sp_state_play) as necessary.
7. Write 0 to the HWPINTF.HWP0IF bit.
(Clear interrupt flag)