E0C88832/88862 TECHNICAL MANUAL
EPSON
45
5 PERIPHERAL CIRCUITS AND THEIR OPERATIO (Output Ports)
BZON: 00FF44H•D0
Controls the buzzer (BZ and BZ) signal output.
When "1" is written: Buzzer signal output ON
When "0" is written: Buzzer signal output OFF
Reading:
Valid
BZON is the output control register for buzzer
signal. When "1" is set to the register, the BZ (BZ)
signal is output from the output port terminal R50
(R51). When "0" is set, the R50 goes LOW (V
SS
) and
the R51 goes HIGH (V
DD
).
To output the BZ signal, "0" must always be set for
the data register R50D. The data register R51D does
not affect the BZ output.
At initial reset, BZON is set to "0" (output OFF).
The BZ signal can be output from R51 only when
the function is selected by mask option.
BZSHT: 00FF44H•D5
Controls the one-shot buzzer output.
When "1" is written: Trigger
When "0" is written: No operation
When "1" is read:
Busy
When "0" is read:
Ready
Writing "1" into BZSHT causes the one-shot output
circuit to operate. The BZ (BZ) signal is output from
the R50 (R51) terminal. The buzzer output is
automatically turned OFF after the time set by
SHTPW has elapsed.
To output the BZ signal, "0" must always be set for
the data register R50D. The data register R51D does
not affect the BZ output.
The one-shot output is only valid when the normal
buzzer output is OFF (BZON = "0") state. The
trigger is invalid during ON (BZON = "1") state.
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)
The operation status of the one-shot output circuit
can be confirmed by reading BZSHT, when the one-
shot output is ON, "1" is read from BZSHTand
when the output is OFF, "0" is read.
At initial reset, BZSHT is set to "0" (ready).
The BZ signal can be output from R51 only when
the function is selected by mask option.
BZSTP: 00FF44H•D6
Forcibly stops the one-shot buzzer output.
When "1" is written: Forcibly stop
When "0" is written: No operation
Reading:
Constantly "0"
By writing "1" into BZSTP, the one-shot buzzer
output can be stopped prior to the elapsing of the
time set with SHTPW.
Writing "0" is invalid and writing "1" except during
one-shot output is also invalid.
When "1" is written to BZSHT and BZSTP simulta-
neously, BZSTP takes precedence and one-shot
output becomes stop status.
Since BZSTP is for writing only, during readout it is
constantly set to "0".
5.5.7 Programming notes
(1) Since the special output signals (TOUT/TOUT,
FOUT, BZ/BZ) are generated asynchronously
from the output control registers (PTOUT,
FOUTON, BZON, BZSHT and BZSTP), when
the signals is turned ON or OFF by the output
control register settings, a hazard of a 1/2 cycle
or less is generated.
(2) The SLP instruction has executed when the
special output signals (TOUT,/TOUT, FOUT,
BZ/BZ) are in the enable status, an unstable
clock is output for the special output at the time
of return from the SLEEP state. Consequently,
when shifting to the SLEEP state, you should set
the special output signal to the disable status
prior to executing the SLP instruction.
(3) When the FOUT frequency is made "f
OSC3
/n",
you must turn on the OSC3 oscillation circuit
before outputting FOUT. A time interval of
several 100
µ
sec to several 10 msec, from the
turning ON of the OSC3 oscillation circuit to
until the oscillation stabilizes, is necessary, due
to the oscillation element that is used. Conse-
quently, if an abnormality occurs as the result of
an unstable FOUT signal being output exter-
nally, you should allow an adequate waiting
time after turning ON of the OSC3 oscillation,
before turning outputting FOUT. (The oscilla-
tion start time will vary somewhat depending
on the oscillator and on the externally attached
parts. Refer to the oscillation start time example
indicated in Chapter 7, "ELECTRICAL CHAR-
ACTERISTICS".)
At initial reset, OSC3 oscillation circuit is set to
OFF state.
∗
FOUT output is available only in the E0C88832.
Summary of Contents for 0C88832
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