Output Ports (R Ports); Configuration Of Output Ports; Mask Option; High Impedance Control - Epson 0C88832 Technical Manual

5.5 Output Ports (R ports)

5.5.1 Configuration of output ports

The E0C88832 is equipped with 5 bits of output
ports (R26, R27, R34, R50 and R51) and the
E0C88862 is equipped with 4 bits of output ports
(R26, R27, R50 and R51).
Figure 5.5.1.1 shows the basic structure (excluding
special output circuits) of the output ports.
The output specification of each port is fixed at
complementary output.
Address
High impedance
control register
Data register
Address
Fig. 5.5.1.1 Structure of output ports
Each output port can be set into high impedance
state by software.
Besides normal DC output, the output ports have
special output functions. The R27, R34 (E0C88832
only) and R50 functions can be selected by software
and the R26 and R51 functions can be selected by

mask option.

5.5.2 Mask option
R26 and R51 output port specifications
R26 ..........

DC output

R51 .......... DC output
The mask option allows selection of special outputs
for the R26 and R51 output ports as well as the DC
output. The R26 port can be set as the TOUT output
port (TOUT signal inverted output) and the R51
port can be set as the BZ output port (buzzer signal
inverted output).
E0C88832/88862 TECHNICAL MANUAL
5 PERIPHERAL CIRCUITS AND THEIR OPERATIO (Output Ports)

5.5.3 High impedance control

The output port can be high impedance controlled
in software.
A high impedance control register is set for each
output port terminal as shown below. Either
complementary output and high impedance state
can be selected with this register.
HZR26: R26 high impedance control register
HZR27: R27 high impedance control register
HZR34: R34 high impedance control register ∗
HZR50: R50 high impedance control register
HZR51: R51 high impedance control register
∗
V
DD
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",
Rxx
it becomes complementary output.
5.5.4 DC output
V As Figure 5.5.1.1 shows, when "1" is written to the
SS
output port data register, the output terminal
switches to HIGH (V
written it switches to LOW (V
output is in a high impedance state, the data
written to the data register is output from the
terminal at the instant when output is switched to
complementary.

5.5.5 Special output

Besides normal DC output, each output port can
also be assigned special output function in software
(R27, R34*, R50) or mask option (R26, R51) as
shown in Table 5.5.5.1.
TOUT output
BZ output
∗
EPSON
Available only in the E0C88832.
) level and when "0" is
DD
Table 5.5.5.1 Special output ports
Output port
R26 TOUT output (mask option)
R27 TOUT output (software selection)
R34* FOUT output (software selection)
R50 BZ output (software selection)
R51 BZ output (mask option)
R34 (FOUT) is available only in the E0C88832.
) level. When
SS
Special output
39