Digital Control Signals; 1-3-1 Local Keyboard; 1-3-2 Ir Remote Control Code - Panasonic Z-421V Technical Manual

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1.2 Digital control signals

1.2.1 1-3-1 local keyboard

The local keyboard is not made in matrix with regular scanning from the microcontroller. Instead one
input of the microcontroller is used to monitor 5 keys. Pressing one key makes the resistance to the
ground vary, and therefore the level at pin 33 of microcontroller

1.2.2 1-3-2 IR remote control code

The IR remote control code used is Philips RC5 code. The RC5 protocol can hand1e up to 4096
commands organized as two sets of 64 commands in up to 32 individually addressable groups, each
of which is allocated to a separate item of equipment.
RC5 remote control transmission protocol:
Bi-phase encoding is used for RC5 code words. As shown in fig. 12 a HIGH to LOW Transition is a
logic 0; one with a LOW to HIGH Transition is a logic 1.
Logic 0 Logic 1
1 bit period
1.7778mS
Fig. 12: bi-phase code
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