II-22
EPSON
S1C62740 TECHNICAL SOFTWARE
CHAPTER 6: PERIPHERAL CIRCUITS (Output Ports)
Output Ports (R00–R03)
6.4
I/O data memory of
the output ports
The control registers of the output ports are shown in Table 6.4.1.
Table 6.4.1 Control registers of output ports
*1 Initial value at the time of initial reset
*5 Constantly "0" when being read
*2 Not set in the circuit
*6 Refer to main manual
*3 Undefined
*7 Page switching in I/O memory is not necessary
*4 Reset (0) immediately after being read
Control of the
general output ports
The S1C62740 has 4 bits (R00–R03) general output ports built-in.
Output port terminals will generate the data written into the
corresponding registers (R00–R03) as it is. The output port termi-
nal goes high (VDD) when "1" is written to the register, and goes low
(VSS) when "0" is written. The output ports R03 and R02 are
initialized to low level (0), R01 and R00 are initialized to high level
(1) after an initial reset.
The output ports R00–R03 are all software programmable for
special use output ports as shown in the later of this section. So
please set the following registers to "0" when want to use R00–R03
as general output ports.
BZR03: E0HD3, BZR02: E0HD2, PTR01: E9HD3, FOR00: E1HD3
Address
Comment
Register
D3
D2
D1
D0
Name
Init
1
0
*1
D4H
R00
FOUT
R/W
R03
BZ
R02
BZ
R01
PTOVF
R00
FOUT
0
1
High
On
High
On
High
Off
High
Off
Low
Off
Low
Off
Low
On
Low
On
R01
PTOVF
R02
BZ
R03
BZ
*7
Output port (R03)
Buzzer inverted output
Output port (R02)
Buzzer output
Output port (R01)
PTOVF output
Output port (R00)
FOUT output
E0H
BZFQ
R/W
BZR03
BZR02
0
BZFQ
0
–
0
R03 port output selection
R02 port output selection
Unused
Buzzer frequency selection
Buzzer
2kHz
DC
4kHz
0
BZR02
BZR03
*2
*5
E1H
FOFQ0
R/W
FOR00
0
FOFQ1
FOFQ0
0
–
0
FOUT
DC
FOFQ1
0
FOR00
*2
*5
R00 port output selection
Unused
FOUT frequency selection
0: 512 Hz, 1: 4096 Hz, 2: fOSC1, 3: fOSC3
R
R/W
R
R/W
E9H
PTRST
W
PTR01
0
PTRUN
PTRST
0
–
0
–
R01 port output selection
Unused
Programmable timer Run/Stop
Programmable timer reset (reload)
PTOVF
Run
Reset
DC
Stop
–
PTRUN
R/W
0
R
PTR01
R/W
*2
*5