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CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Output Ports)
R00HIZ–R03HIZ: R0 port high impedance control register (FF30H)
R10HIZ–R13HIZ: R1 port high impedance control register (FF32H)
R20HIZ–R23HIZ: R2 port high impedance control register (FF34H)
Controls high impedance output of the output port.
When "1" is written: High impedance
When "0" is written: Data output
Reading: Valid
By writing "0" to the high impedance control register, the corresponding output terminal outputs accord-
ing to the data register. When "1" is written, it shifts into high impedance status.
When an output port (R00–R03, R10–R13) is used for special output, fix the corresponding high imped-
ance control register at "0" (data output).
At initial reset, these registers are set to "0".
R00–R03: R0 output port data register (FF31H)
R10–R13: R1 output port data register (FF33H)
R20–R23: R2 output port data register (FF35H)
Set the output data for the output ports.
When "1" is written: High level output
When "0" is written: Low level output
Reading: Valid
The output port terminals output the data written in the corresponding data registers without changing
it. When "1" is written to the register, the output port terminal goes high (V
the output port terminal goes low (V
When an output port (R00–R03, R10–R13) is used for special output, fix the corresponding data register at
"1".
At initial reset, these registers are all set to "1".
XBZOUT: R00 output selection register (FF65H•D0)
Selects the R00 terminal function.
When "1" is written: XBZ output
When "0" is written: General-purpose DC output
Reading: Valid
When using the R00 terminal for the XBZ output, write "1" to this register. Furthermore, fix the R00
register at "1" and the R00HIZ register at "0". Refer to Section 4.12, "Sound Generator", for controlling the
XBZ output.
When using the R00 output port for a general-purpose output, fix this register at "0".
At initial reset, this register is set to "0".
BZOUT: R01 output selection register (FF65H•D1)
Selects the R01 terminal function.
When "1" is written: BZ output
When "0" is written: General-purpose DC output
Reading: Valid
When using the R01 terminal for the BZ output, write "1" to this register. Furthermore, fix the R01 register
at "1" and the R01HIZ register at "0". Refer to Section 4.12, "Sound Generator", for controlling the BZ
output.
When using the R01 output port for a general-purpose output, fix this register at "0".
At initial reset, this register is set to "0".
38
).
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EPSON
), and when "0" is written,
DD
S1C63558 TECHNICAL MANUAL
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