MC9S12A256 Motorola, MC9S12A256 Datasheet - Page 60

• Manufacturer Part Number: MC9S12A256
• Description: MC9S12DT256 Device User Guide V03.03
• Manufacturer: Motorola

MC9S12DT256 Device User Guide — V03.03
2.3.9 PAD7 / AN07 / ETRIG0 — Port AD Input Pin of ATD0
PAD7 is a general purpose input pin and analog input AN7 of the analog to digital converter ATD0. It can
act as an external trigger input for the ATD0.
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.
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