E0C6006 TECHNICAL MANUAL
EPSON
21
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Output Ports)
4.5.4 I/O memory of output ports
Table 4.5.4.1 shows the I/O address and the control bits for the output port.
Table 4.5.4.1 Control bits of output port
Address
Comment
D3
D2
Register
D1
D0
Name
Init
∗
1
1
0
0FCH
R03
BZ
R02
BZ
FOUT
R01
R00
R/W
R03
BZ
R02
BZ/FOUT
R01
R00
0
0
0
0
0
0
High
On
High
On
High
High
Low
Low
Low
Low
Low
Low
R03 output port data
Signal on/off when BZ is selected. (mask option)
R02 output port data
Signal on/off when BZ/FOUT is selected. (mask option)
R01 output port data
R00 output port data
∗
1
∗
2
Initial value at initial reset
Not set in the circuit
∗
5 Undefined
∗
3
∗
4
Always "0" being read
Reset (0) immediately after being read
R00–R03: Output port data (0FCH)
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 to the corresponding registers (R00–R03) without
changing it. When "1" is written to the register, the output port terminal goes high (V
DD
), and when "0" is
written, the output port terminal goes low (V
SS
).
At initial reset, these registers are all set to "0".
R02 (when FOUT is selected): Special output control (0FCH•D2)
Controls the FOUT (clock) output.
When "1" is written: Clock output
When "0" is written: Low level (DC) output
Reading: Valid
When "1" is written to the FOUT (R02) register, the FOUT (R02) terminal outputs the FOUT signal. When
"0" is written, the terminal goes low.
At initial reset, this register is set to "0".
R02, R03 (when buzzer output is selected): Special output port data (0FCH•D2, D3)
Controls the buzzer output.
When "1" is written: Buzzer output
When "0" is written: Low level (DC) output
Reading: Valid
The BZ and BZ outputs can be controlled by writing data to the R02 and R03 registers.
At initial reset, these registers are set to "0".
4.5.5 Programming note
The FOUT and buzzer output signals may produce hazards when the output ports R02 and R03 are
turned on or off.