SIC63616-(Rev. 1.0) NO. P58
3240-0412
These registers enable the built-in pull-down resistor to be effective during input mode in 1-bit units. (The
pull-down resistor is included into the ports selected by mask option.)
By writing "1" to the pull-down control register, the corresponding I/O ports are pulled down during input
mode, while writing "0" or output mode disables the pull-down function.
At initial reset, these registers are all set to "1", so the pull-down function is enabled.
The pull-down control register of the port in which the pull-down resistor is not included becomes a
general-purpose register. The register of the port that is set as output for the serial interface, input/output
for the R/f converter or a special output can also be used as a general-purpose register that does not affect
the pull-down control.
The pull-down control register of the port that is set as input for the serial interface functions the same as
the I/O port.
SMT10–SMT01: P1 port input interface level select register (FF27H)
SMT20–SMT23: P2 port input interface level select register (FF2BH)
SMT40–SMT43: P4 port input interface level select register (FF33H)
Selects an input interface level.
When "1" is written: CMOS Schmitt level
When "0" is written: CMOS level
Reading: Valid
These registers select the input interface level of the I/O ports in 1-bit units.
When "1" is written to SMTxx, the corresponding I/O port Pxx is configured with a CMOS Schmitt level
input interface. When "0" is written, the port is configured with a CMOS level input interface. (P0x is the
fixed setting for CMOS Schmitt level.)
At initial reset, these registers are set to "1".
SIP00–SIP03: P1 port interrupt select register (FF3CH)
SIP10–SIP13: P4 port interrupt select register (FF3EH)
Selects the ports used for the key input interrupt from P10–P13 and P40–P43.
When "1" is written: Interrupt enable
When "0" is written: Interrupt disable
Reading: Valid
By writing "1" to an interrupt select register (SIP00–SIP03, SIP10–SIP13), the corresponding I/O port (P10
–P13, P40–P43) is enabled to generate interrupts. When "0" is written, the I/O port does not affect the
interrupt generation.
Reactivating from SLEEP status can only be done by generation of a key input interrupt factor. Therefore
when using the SLEEP function, it is necessary to set the interrupt select register (SIPxx = "1") of the port to
be used for releasing SLEEP status before executing the SLP instruction.
At initial reset, these registers are set to "0".
PCP00–PCP03: P1 port interrupt polarity select register (FF3DH)
PCP10–PCP13: P4 port interrupt polarity select register (FF3FH)
Sets the interrupt conditions.
When "1" is written: Falling edge
When "0" is written: Rising edge
Reading: Valid
When "1" is written to an interrupt polarity select register (PCP00–PCP03, PCP10–PCP13), the corresponding
I/O port (P10–P13, P40–P43) generates an interrupt at the falling edge of the input signal. When "0" is
written, the I/O port generates an interrupt at the rising edge of the input signal.
At initial reset, these registers are set to "1".
Содержание S1C63616
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