21 HW Processor (HWP) and Sound Output
21-10
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
Mute
Mute control
The sound can be muted during playback 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 0x07 or 0x08.* (Select Mute 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 mutes the sound from this point.
6. Confirm that the STATE_
n
.STATE[15:0] bits = 0x0004 (sp_state_mute) as necessary.
7. Write 0 to the HWPINTF.HWP0IF bit.
(Clear interrupt flag)
The above operation mutes the sound while playback output continues.
*
Two mute commands are available. Setting the COMMAND_
n
.COMMAND[7:0] bits to 0x07 selects the
Mute Immediately command; setting to 0x08 selects the Mute after Current Phrase command.
Mute Immediately command
When this command is issued by the trigger bit, the sound is muted immediately. At this time, a
smoothing (fade-out) process for the playback output signal is carried out to suppress the occurrence of
noise.
Command execution
(Mute/Pause/Stop Immediately command
)
Time
Smoothing process
Sound level
Figure 21.4.1.2 Smoothing Process when Playback Output is Suspended
Mute after Current Phrase command
The sound is muted after ending the phrase that is being output when the command is issued.
Command execution
(Mute/Pause/Stop after Current Phrase command)
Output suspending position
“The temperature is set at” is output before being muted.
Phrase 0
Phrase 1
Sentence example: “The temperature is set at / 41 degrees.”
Figure 21.4.1.3 Example of Waiting for End of Phrase
Mute release
The mute state can be released with the procedure shown below.
1. Confirm that the STATE_
n
.STATE[15:0] bits = 0x0004 (sp_state_mute).
2. Confirm that the STATUS.READY bit = 1.
(Command acceptable)
3. Set the COMMAND_
n
.COMMAND[7:0] bits to 0x09.
(Select Release Mute 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)
From this point, the volume returns to the level it was before being muted.
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)