
S1C88348/317/316/308 TECHNICAL HARDWARE
EPSON
I-63
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Output Ports)
5.6.2 Mask option
Output ports R00–R07 and R10–R17 output
specifications
R00 ..... s
s Complementary s
s Nch open drain
R01 ..... s
s Complementary s
s Nch open drain
R02 ..... s
s Complementary s
s Nch open drain
R03 ..... s
s Complementary s
s Nch open drain
R04 ..... s
s Complementary s
s Nch open drain
R05 ..... s
s Complementary s
s Nch open drain
R06 ..... s
s Complementary s
s Nch open drain
R07 ..... s
s Complementary s
s Nch open drain
R10 ..... s
s Complementary s
s Nch open drain
R11 ..... s
s Complementary s
s Nch open drain
R12 ..... s
s Complementary s
s Nch open drain
R13 ..... s
s Complementary s
s Nch open drain
R14 ..... s
s Complementary s
s Nch open drain
R15 ..... s
s Complementary s
s Nch open drain
R16 ..... s
s Complementary s
s Nch open drain
R17 ..... s
s Complementary s
s Nch open drain
Output ports R00–R07 and R10–R17 can be used to
select output specification for each port (1 bit) by
mask option.
The output specification can be selected for either
complementary output or Nch open drain output.
Nch open drain output is rendered suitable for
purposes as key matrix common output.
For unused input ports, select the default setting of
"Complementary".
Note: When Nch open drain has been selected,
voltage in excess of the supply voltage
range must not applied to the output port
terminal.
5.6.3 High impedance control
The output port can be high impedance controlled
in software.
This makes it possible to share output signal lines
with an other external device.
A high impedance control register is set for each
series of output port terminals as shown below.
Either complementary output and high impedance
state can be selected with this register.
Table 5.6.3.1 Correspondence between output ports and
high impedance control registers
*
1 In the S1C88308, this is general purpose register
with read/write capabilities.
*
2 This is a 2-bit reserved register, it can be used as
a general purpose register with read/write
capabilities.
When a high impedance control register HZRxx is
set to "1", the corresponding output port terminal
becomes high impedance state and when set to "0",
it becomes complementary output.
Register
Output port terminal
HZR0L
HZR0H
HZR1L
HZR1H
HZR20
HZR21
HZR22
HZR23
HZR24
HZR25
HZR26
HZR27
HZR30
HZR31
HZR32
HZR33
HZR34
HZR35
HZR36
HZR37
HZR4L
HZR4H
HZR50
HZR51
R00–R03
R04–R07
R10–R13
R14–R17
R20
R21
R22
R23
R24
R25
R26
R27
R30
R31
R32
R33
R34
R35
R36
R37
–
R50
R51
*1
*2
*1