Nintendo GAME BOY Programming Manual page 41

The following illustrates the flow for implementing a connection.
Start of infrared
communication
Read bit 1 of RP
Register
Value read=0?
Pulse-width measurement
(software measurement of
High and Low periods)
Received signal a
proper connecting
pulse?
Send connecting pulse
Connection established
(receiver)
Header
Light emission by sender
Light detection by receiver
One byte indicating the data type and 1 byte indicating the number of transmitted data
are sandwiched between synchronous pulses.
Data
Light emission by sender
Light detection by receiver
Between 1 and 255 bytes of transmitted data are sandwiched between synchronous
pulses.
N
Transmission
Signal received?
N
Y
N
Y
Communication Error
Synchronous pulse
Synchronous pulse
Y
Transmission of
connecting pulse
Start of reception,
measurement of width of
received pulse
N
Is the received signal
the correct connecting
pulse?
Y
Connection established
(sender)
OOH Number of data transmitted
Transmitted data
41
Chapter 1: System
Synchronous pulse
Synchronous pulse