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Chapter 2 Port Integration Module (S12XEPIMV1)
MC9S12XE-Family Reference Manual Rev. 1.07
Freescale Semiconductor
177
PortEpinPE[5]anbeusedforeithergeneral-purposeI/O,asTAGLOinput,REoutputorasMODBinput
during reset.
Port E pin PE[4] an be used for either general-purpose I/O or as the free-running clock ECLK output
running at the Bus Clock rate or at the programmed divided clock rate. The clock output is always enabled
in emulation modes.
Port E pin PE[3] an be used for either general-purpose I/O, as LSTRB or LDS output, or as EROMCTL
input during reset.
Port E pin PE[2] an be used for either general-purpose I/O, or as RW or RE output.
Port E pin PE[1] can be used for either general-purpose input or as the level- or falling edge-sensitive IRQ
interrupt input. IRQ will be enabled by setting the IRQEN configuration bit (
2.3.17/2-112
) and clearing
the I-bit in the CPU condition code register. It is inhibited at reset so this pin is initially configured as a
simple input with a pull-up.
PortEpinPE[0]canbeusedforeithergeneral-purposeinputorasthelevel-sensitiveXIRQinterruptinput.
XIRQ can be enabled by clearing the X-bit in the CPU condition code register. It is inhibited at reset so
this pin is initially configured as a high-impedance input with a pull-up.
Port E pins PE[5] and PE[6] are configured for reduced input threshold in certain modes (refer to
S12X_EBI section).
2.4.3.5
Port K
Port K pins PK[7:0] can be used for either general-purpose I/O, or with the external bus interface. In this
casePortKpinsPK[6:0]areassociatedwiththeexternaladdressbusoutputsADDR22-ADDR16andPK7
is associated to the EWAIT input.
Port K pin PE[7] is configured for reduced input threshold in certain modes (refer to S12X_EBI section).
2.4.3.6
Port T
This port is associated with the ECT module.
Port T pins PT[7:0] can be used for either general-purpose I/O, or with the channels of the Enhanced
Capture Timer.
2.4.3.7
Port S
This port is associated with SCI0, SCI1 and SPI0.
Port S pins PS[7:4] can be used either for general-purpose I/O, or with the SPI0 subsystem.
Port S pins PS[3:2] can be used either for general-purpose I/O, or with the SCI1 subsystem.
Port S pins PS[1:0] can be used either for general-purpose I/O, or with the SCI0 subsystem.
The SPI0 pins can be re-routed.