S1C62740 TECHNICAL HARDWARE
EPSON
I-37
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Output Ports)
When the PTOVF output is selected, ON/OFF of the signal output
can be controlled by the R01 register.
At initial reset, this register is set to "0".
BZR02, BZR03:
R02, R03 output selection
register
(E0HD2, D3)
Selects the output type for the R02 and R03 terminals.
When "1" is written: Buzzer signal output
When "0" is written: DC output
Reading: Valid
By setting the register BZR02 to "1", R02 is set to BZ (buzzer
signal) output port and by setting the register BZR03 to "1", R03 is
set to BZ (buzzer inverted signal) output port. When BZR02 and
BZR03 are set to "0", R02 and R03 become the regular DC output
ports.
When the buzzer output and the buzzer inverted output are se-
lected, ON/OFF of the buzzer outputs can be controlled by the R02
and R03 registers, respectively.
At initial reset, these register are set to "0".
R00–R03 (when DC output):
Output port data
(D4H)
Sets the output data for the output ports.
When "1" is written: High output
When "0" is written: Low output
Reading: Valid
The output port terminals output the data written in the corre-
sponding registers (R00–R03) without changing it. When "1" is
written in the register, the output port terminal goes high (VDD),
and when "0" is written, the output port terminal goes low (VSS).
At initial reset, R00 and R01 are set to "1"; R02 and R03 are set to
"0".
R02, R03 (when BZ and BZ
output is selected):
Special output port data
(D4HD2, D3)
BZFQ:
Buzzer frequency selection
register
(E0HD0)
Selects the frequency of the buzzer signal.
When "1" is written: 2 kHz
When "0" is written: 4 kHz
Reading: Valid
When "1" is written to register BZFQ, the frequency of the buzzer
signal is set in 2 kHz, and in 4 kHz when "0" is written.
At initial reset, this register is set to "0".
These bits control the output of the buzzer signals (BZ, BZ).
When "1" is written: Buzzer signal is output
When "0" is written: Low level (DC) is output
Reading: Valid
BZ (buzzer signal) output is controlled by writing data to R10, and
BZ (buzzer inverted signal) output is controlled by writing data to
R13. At initial reset, R02 and R03 are set to "0".