SIC63616-(Rev. 1.0) NO. P140
3240-0412
ENON: Envelope On/Off control register (FF44H•D1)
Controls the addition of an envelope onto the buzzer signal.
When "1" is written: On
When "0" is written: Off
Reading: Valid
Writing "1" to ENON causes an envelope to be added during buzzer signal output. When a "0" has been
written, an envelope is not added.
At initial reset, this register is set to "0".
ENRST: Envelope reset (FF44H•D2)
Resets the envelope.
When "1" is written: Reset
When "0" is written: No operation
Reading: Always "0"
Writing "1" to ENRST resets envelope and the duty ratio becomes maximum. If an envelope has not been
added (ENON = "0") and if no buzzer signal is being output, the reset becomes invalid. Writing "0" is also
invalid.
This bit is dedicated for writing, and is always "0" for reading.
ENRTM: Envelope releasing time select register (FF44H•D3)
Selects the envelope releasing time that is added to the buzzer signal.
When "1" is written: 1.0 sec (125 msec × 7 = 875 msec)
When "0" is written: 0.5 sec (62.5 msec × 7 = 437.5 msec)
Reading: Valid
The releasing time of the digital envelope is determined by the time for converting the duty ratio.
When "1" is written to ENRTM, it becomes 125 msec (8 Hz) units and when "0" is written, it becomes 62.5
msec (16 Hz) units.
At initial reset, this register is set to "0".
SHTPW: One-shot buzzer pulse width setting register (FF45H•D0)
Selects the output time of the one-shot buzzer.
When "1" is written: 125 msec
When "0" is written: 31.25 msec
Reading: Valid
Writing "1" to SHTPW causes the one-short output time to be set at 125 msec, and writing "0" causes it to be
set to 31.25 msec. It does not affect normal buzzer output.
At initial reset, this register is set to "0".
BZSHT: One-shot buzzer trigger/status (FF45H•D1)
Controls the one-shot buzzer output.
• When writing
When "1" is written: Trigger
When "0" is written: No operation
Writing "1" to BZSHT causes the one-short output circuit to operate and a buzzer signal to be output.
This output is automatically turned off after the time set by SHTPW has elapsed. The one-shot output is
only valid when the normal buzzer output is off (BZE = "0") and will be invalid when the normal buzzer
output is on (BZE = "1"). When a re-trigger is assigned during a one-shot output, the one-shot output time
set with SHTPW is measured again from that point (time extension).