PM I/O Port
Pokemon Mini I/O Port Overview
The Pokemon Mini provides a tri-state 8-bit I/O port. Each bit is mapped to a different pin, and each has it's own configurable direction, providing a relatively powerful interface to external hardware.
The I/O interface is shared among various parts of hardware, so care must be taken when altering the direction and data as not to disturb other processes.
|6||Always 1 (Pull-Up?)|
|7||(IR Transmitter? Used to double power?)|
How the I/O Port Works
The I/O Port is configured using 2 8-bit registers. IO_DIR selects the data direction of the respective pin. Reset is an input bit, Set is an output pin. IO_DATA provides both a input read value as well as the latch to drive output, the value read back from this port depends on the state of IO_DIR.
When a pin is set to input, and there is no data being externally driven on the pin, the state is left undetermined as that bit is defined as floating.
The EEPROM is a 24xx64 alike 64 kbit serial EEPROM using an I2C interface.
Rumble is simply a pin used to drive a motor, which is likely driven through an amplifier. For rumble to be active, the rumble pin must be set for output with a logical 1 driving the pin.
IR is a unmodulated diode transceiver. Setting the IR Disable to output and setting data to logical 1, disables the receiver.