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Figure 5-12 Block Diagram of the IR Emitter LED and Receiver Demonstration
Figure 5-12
shows the block diagram of the design. It mainly implement a IR TX Controller and a
IR RX Controller. When KEY0 is pressed, Data test pattern generator continuously generates data
to the IR TX Controller. When IR TX Controller works, it will format the sending data into NEC IR
transmission protocol and send it out through IR emitter LED. IR receiver will decode the received
data and display it on six HEXs. Also, user can use a remote controller to sending data to IR
Receiver. The main function of IR TX /RX controller and IR remote in this demonstration will be
described in below:
IR TX Controller
User can input 8-bit address and 8-bits command into IR TX Controller. IR TX Controller will encode
the the address and command first , and send it out according to NEC IR transmission protocol through
IR emitter LED. Note that the input clock of the Controller should be 50MHz.
The NEC IR transmission protocol uses pulse distance encoding of the message bits. Each pulse burst is
562.5µs in length, at a carrier frequency of 38kHz (26.3µs). As shown in
Figure 5-13
,Logical bits are
transmitted as follows:
•
Logical '0' – a 562.5µs pulse burst followed by a 562.5µs space, with a total transmit time
of 1.125ms
•
Logical '1' – a 562.5µs pulse burst followed by a 1.6875ms space, with a total transmit time
Summary of Contents for DE1-SOC
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