MC9S12KG128_10 Datasheet, PDF (36/606 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 1 MC9S12KG128 Device Overview (MC9S12KG128V1)
1.2.2.52 PS2 / RXD1 — Port S I/O Pin 2
PS2 is a general purpose input or output pin. It can be configured as the receive pin RXD of Serial
Communication Interface 1 (SCI1).
1.2.2.53 PS1 / TXD0 — Port S I/O Pin 1
PS1 is a general purpose input or output pin. It can be configured as the transmit pin TXD of Serial
Communication Interface 0 (SCI0).
1.2.2.54 PS0 / RXD0 — Port S I/O Pin 0
PS0 is a general purpose input or output pin. It can be configured as the receive pin RXD of Serial
Communication Interface 0 (SCI0).
1.2.2.55 PT[7:0] / IOC[7:0] — Port T I/O Pins [7:0]
PT7-PT0 are general purpose input or output pins. They can be configured as input capture or output
compare pins IOC7-IOC0 of the Timer (TIM).
1.2.3 Power Supply Pins
MC9S12KG128 power and ground pins are described below.
NOTE
All VSS pins must be connected together in the application.
1.2.3.1 VDDX,VSSX — Power Supply Pins for I/O Drivers
External power and ground for I/O drivers. Because fast signal transitions place high, short-duration
current demands on the power supply, use bypass capacitors with high-frequency characteristics and place
them as close to the MCU as possible. Bypass requirements depend on how heavily the MCU pins are
loaded.
1.2.3.2 VDDR, VSSR — Power Supply Pins for I/O Drivers & for Internal Voltage
Regulator
External power and ground for I/O drivers and input to the internal voltage regulator. Because fast signal
transitions place high, short-duration current demands on the power supply, use bypass capacitors with
high-frequency characteristics and place them as close to the MCU as possible. Bypass requirements
depend on how heavily the MCU pins are loaded.
1.2.3.3 VDD1, VDD2, VSS1, VSS2 — Power Supply Pins for Internal Logic
Power is supplied to the MCU through VDD and VSS. Because fast signal transitions place high,
short-duration current demands on the power supply, use bypass capacitors with high-frequency
characteristics and place them as close to the MCU as possible. This 2.5V supply is derived from the
MC9S12KG128 Data Sheet, Rev. 1.16
36
Freescale Semiconductor