Motorola MC9S12GC-Family - Manual (Page 61)

Device User Guide — 9S12C128DGV1/D V01.05
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2.3.14 PE1 / IRQ — Port E input Pin [1] / Maskable Interrupt Pin
The IRQ input provides a means of applying asynchronous interrupt requests to the MCU. Either falling
edge-sensitive triggering or level-sensitive triggering is program selectable (INTCR register). IRQ is
always enabled and configured to level-sensitive triggering out of reset. It can be disabled by clearing
IRQEN bit (INTCR register). When the MCU is reset the IRQ function is masked in the condition code
register. This pin is always an input and can always be read. There is an active pull-up on this pin while in
reset and immediately out of reset. The pull-up can be turned off by clearing PUPEE in the PUCR register.
2.3.15 PE0 / XIRQ — Port E input Pin [0] / Non Maskable Interrupt Pin
The XIRQ input provides a means of requesting a non maskable interrupt after reset initialization. During
reset, the X bit in the condition code register (CCR) is set and any interrupt is masked until MCU software
enables it. Because the XIRQ input is level sensitive, it can be connected to a multiple-source wired-OR
network. This pin is always an input and can always be read. There is an active pull-up on this pin while
in reset and immediately out of reset. The pull-up can be turned off by clearing PUPEE in the PUCR
register.
2.3.16 PAD[7:0] / AN[7:0] — Port AD I/O Pins [7:0]
PAD7-PAD0 are general purpose I/O pins and also analog inputs for the analog to digital converter. In
order to use a PAD pin as a standard I/O, the corresponding ATDDIEN register bit must be set. These bits
are cleared out of reset to configure the PAD pins for A/D operation.
When the A/D converter is active in multi-channel mode, port inputs are scanned and converted
irrespective of PortAD configuration. Thus PortAD pins that are configured as digital inputs or digital
outputs are also converted in the A/D conversion sequence.
2.3.17 PP[7] / KWP[7] — Port P I/O Pin [7]
PP7 is a general purpose input or output pin, shared with the keypad interrupt function. When configured
as an input, it can generate interrupts causing the MCU to exit STOP or WAIT mode. This pin is not
available in the 48 / 52 pin package versions.
2.3.18 PP[6] / KWP[6]/ROMCTL — Port P I/O Pin [6]
PP6 is a general purpose input or output pin, shared with the keypad interrupt function. When configured
as an input, it can generate interrupts causing the MCU to exit STOP or WAIT mode. This pin is not
available in the 48 / 52 pin package versions. During MCU expanded modes of operation, this pin is used
to enable the Flash EEPROM memory in the memory map (ROMCTL). At the rising edge of RESET, the
state of this pin is latched to the ROMON bit.
PP6=1 in emulation modes equates to ROMON =0 (ROM space externally mapped)
PP6=0 in expanded modes equates to ROMON =0 (ROM space externally mapped)