Freescale Semiconductor, Inc.
Pinout and Signal Descriptions
Port Signals
Setting the RDPE bit in register RDRIV causes all port E outputs to have
reduced drive level. RDRIV can be written once after reset. RDRIV is not
in the address map in peripheral mode. Refer to Bus Control and
Input/Output.
3.5.4 Port H
Port H pins are used for key wake-ups that can be used with the pins
configured as inputs or outputs. The key wake-ups are triggered with
either a rising or falling edge signal (KWPH). An interrupt is generated if
the corresponding bit is enabled (KWIEH). If any of the interrupts is not
enabled, the corresponding pin can be used as a general purpose I/O
pin. Refer to I/O Ports with Key Wake-up.
Register DDRH determines whether each port H pin is an input or output.
Setting a bit in DDRH makes the corresponding bit in port H an output;
clearing a bit in DDRH makes the corresponding bit in port H an input.
The default reset state of DDRH is all zeros.
Register KWPH not only determines what type of edge the key wake ups
are triggered, but it also determines what type of resistive load is used
for port H input pins when PUPH bit is set in the PUCR register. Setting
a bit in KWPH makes the corresponding key wake up input pin trigger at
rising edges and loads a pull down in the corresponding port H input pin.
Clearing a bit in KWPH makes the corresponding key wake up input pin
trigger at falling edges and loads a pull up in the corresponding port H
input pin. The default state of KWPH is all zeros.
Setting the RDPH bit in register RDRIV causes all port H outputs to have
reduced drive level. RDRIV can be written once after reset. RDRIV is not
in the address map in peripheral mode. Refer to Bus Control and
Input/Output.
3.5.5 Port J
Port J pins are used for key wake-ups that can be used with the pins
configured as inputs or outputs. The key wake-ups are triggered with
either a rising or falling edge signal (KWPJ). An interrupt is generated if
MC68HC912DG128 — Rev 3.0
Technical Data
Pinout and Signal Descriptions
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