Gameboy Link Port Info


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The link port emulation isn’t too bad once you break down the main points.

Bytes are exchanged between units. It is not like RS-232 with RX and TX lines. Two units will exchange bytes at the same time.

The reason is because the bytes are transfered by being shifted into a shift register.

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This lead to the next point. Only one unit can clock the shift register at a time. The Gameboy can be configured into 2 clocking modes, Internal and External.

In Internal mode, the Gameboy in clock the shift register itself. In External mode, the Gameboy is waiting for the opponent unit, if any, to clock the shift register.

The Gameboy in Internal mode is the Master device and the Gameboy in External mode is the Slave device.