Output Ports (R Ports); Configuration Of Output Ports; High Impedance Control; Dc Output - Epson S1C88650 Technical Manual

5.6 Output Ports (R ports)

5.6.1 Configuration of output ports

The S1C88650 is equipped with 26 bits of output
ports (R00–R07, R10–R17, R20–R25, R30–R33).
Depending on the bus mode setting, the configura-
tion of the output ports may vary as shown in the
table below.
Table 5.6.1.1 Configuration of output ports
Terminal
Single chip
R00 Output port R00
R01 Output port R01
R02 Output port R02
R03 Output port R03
R04 Output port R04
R05 Output port R05
R06 Output port R06
R07 Output port R07
R10 Output port R10
R11 Output port R11
R12 Output port R12
R13 Output port R13
R14 Output port R14
R15 Output port R15
R16 Output port R16
R17 Output port R17
R20 Output port R20
R21 Output port R21
R22 Output port R22
R23 Output port R23
R24 Output port R24
R25 Output port R25
R30 Output port R30
R31 Output port R31
R32 Output port R32
R33 Output port R33
Only the configuration of the output ports in single
chip mode will be discussed here. With respect to
bus control, see "5.2 System Controller and Bus
Control".
Figure 5.6.1.1 shows the basic structure of the
output ports.
Address
High impedance
control register
Data register
Address
Fig. 5.6.1.1 Structure of output ports
S1C88650 TECHNICAL MANUAL
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Output Ports)
Bus mode
Expansion
Address A0
Address A1
Address A2
Address A3
Address A4
Address A5
Address A6
Address A7
Address A8
Address A9
Address A10
Address A11
Address A12
Address A13
Address A14
Address A15
Address A16
Address A17
Address A18
Address A19
RD signal
WR signal
Output port R30/CE0 signal
Output port R31/CE1 signal
Output port R32/CE2 signal
Output port R33/BACK signal
V
DD
Rxx
V
SS
In expansion mode, the data registers and high
impedance control registers of the output ports
used for bus function can be used as general
purpose registers with read/write capabilities. This
will not in any way affect bus signal output.
The output specification of each output port is as
complementary output with high impedance
control in software possible.

5.6.2 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 5.6.2.1 High impedance control registers
Register
HZR0L
HZR0H
HZR1L
HZR1H
HZR20
HZR21
HZR22
HZR23
HZR24
HZR25
HZR30
HZR31
HZR32
HZR33
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.

5.6.3 DC output

As Figure 5.6.1.1 shows, when "1" is written to the
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.
EPSON
Output port terminal
R00–R03
R04–R07
R10–R13
R14–R17
R20
R21
R22
R23
R24
R25
R30
R31
R32
R33
) level and when "0" is
DD
) level. When
SS
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