
MC9S12DJ64 Device User Guide — V01.02
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2.3.10 PAD[06:00] / AN[06:00] — Port AD Input Pins of ATD0
PAD06 - PAD00 are general purpose input pins and analog inputs AN[6:0] of the analog to digital
converter ATD0.
2.3.11 PA[7:0] / ADDR[15:8] / DATA[15:8] — Port A I/O Pins
PA7-PA0 are general purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the multiplexed external address and data bus.
2.3.12 PB[7:0] / ADDR[7:0] / DATA[7:0] — Port B I/O Pins
PB7-PB0 are general purpose input or output pins. In MCU expanded modes of operation, these pins are
used for the multiplexed external address and data bus.
2.3.13 PE7 / NOACC / XCLKS — Port E I/O Pin 7
PE7 is a general purpose input or output pin. During MCU expanded modes of operation, the NOACC
signal, when enabled, is used to indicate that the current bus cycle is an unused or “free” cycle. This signal
will assert when the CPU is not using the bus.
The XCLKS is an input signal which controls whether a crystal in combination with the internal Colpitts
(low power) oscillator is used or whether Pierce oscillator/external clock circuitry is used. The state of this
pin is latched at the rising edge of RESET. If the input is a logic low the EXTAL pin is configured for an
external clock drive or a Pierce Oscillator. If input is a logic high a Colpitts oscillator circuit is configured
on EXTAL and XTAL. Since this pin is an input with a pull-up device during reset, if the pin is left
floating, the default configuration is a Colpitts oscillator circuit on EXTAL and XTAL.
Table 2-2 Clock Selection Based on PE7
PE7
Description
1
Colpitts Oscillator selected
0
Pierce Oscillator or external clock selected