12x baud
multiple
0.25 or 1/4 duty cycle pulse
0.33 or 1/3 duty cycle pulse
0.42 or 5/12 duty cycle pulse
0.5 or 1/2 duty cycle pulse
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uart-015
Public Version
www.ti.com
UART/IrDA/CIR Environment
19.2.6.2.2 Pulse Duty Cycle
The programmer can choose between four possible duty cycles for modulation pulses by setting the
appropriate value in the UART3.
[5:4] CIR_PULSE_MODE field (1/4, 1/3, 5/12, or 1/2).
shows the CIR modulation duty cycles.
Figure 19-14. CIR Modulation Duty Cycle
The transmission logic ensures that all pulses are transmitted completely (that is, no cutoff during
transmission). Furthermore, while transmitting continuous bytes back-to-back, no delay is inserted
between 2 transmitted bytes. Thus, software must handle the delay between consecutively transmitted
bytes if the receiving end needs it.
19.2.6.2.3 Consumer IR Encoding/Decoding
There are two methods of encoding for remote control applications. The first method uses time-extended
bit forms (a variable pulse distance, or duration, in which the difference between a logic 1 and logic 0 is
the length of the pulse width).
The second encoding method uses a biphase in which the encoding of the logic 0 and logic 1 is in the
change of signal level from 1 to 0 or 0 to 1, respectively. Japanese manufacturers favor pulse duration
encoding; European manufacturers favor biphase encoding.
The CIR mode uses a completely flexible free-format encoding in which the TX FIFO is transmitted as a
modulated pulse with duration T.
Similarly, 0 is transmitted as a blank duration T. The MPU constructs and deciphers the protocol of the
data. For example, the RC-5 protocol using Manchester encoding can be emulated as using a 01 pair for
1 and a 10 pair for 0 (see
2883
SWPU177N – December 2009 – Revised November 2010
UART/IrDA/CIR
Copyright © 2009–2010, Texas Instruments Incorporated
Содержание OMAP36 Series
Страница 174: ...174 List of Tables SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 692: ...692 MPU Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 1084: ...1084 IVA2 2 Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 1990: ...1990 2D 3D Graphics Accelerator SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2334: ...2334 Memory Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2700: ...2700 Memory Management Units SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2868: ...2868 HDQ 1 Wire SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2974: ...2974 UART IrDA CIR SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3054: ...3054 Multichannel SPI SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3462: ...3462 MMC SD SDIO Card Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3508: ...3508 General Purpose Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3584: ...3584 Initialization SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3648: ...3648 Debug and Emulation SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...