Nintendo GAME BOY Programming Manual page 38

Game Boy Programming Manual
The following illustrates signals from a sender.
Double-speed
Normal speed
"0" signal sent
Double-speed
Normal speed
"1" signal sent
Double speed
Normal speed
Synchronous pulses
Double-speed
Normal speed
Connected pulses
Scatter in the source oscillation of Game Boy Color produces slight individual
differences.
2.6.3.4 Preparing for Data Transmission and Reception
To use infrared communication, data reception must be enabled by setting bits 6 and 7 of
Game Boy Color RP register to 1. However, even with both of these bits set to 1, data
cannot immediately be received. After setting bits 6 and 7 to 1, at least 50 ms should be
allowed to pass before using the infrared port.
25
25
36
40
50
99
60 100
120 200
38
55 (units: µs)
76
70
93
65
132
60
120
1
RP register bit 0
0
1
0
1
0
1
0