EM78468
8-BIT Microcontroller
4.10 Infrared Remote Control Application / PWM Waveform Generate
This LSI can output infrared carrier in a friendly manner or in PWM standard waveform.
The IR and PWM waveform generated functions include an 8-bits down-count timer,
high-pulse width timer, low-pulse width timer, and IR control register. The IR system
block diagram is show in Fig.21, The IROUT pin waveform is determined by IR control
register (RE), IOC90 (Counter 1, 2 control register), IOCA0 (high-pulse width timer,
low-pulse width timer control register), IOCC0 (Counter 2 preset), IOCD0 (high-pulse
width timer preset register), and IOCE0 (low-pulse width timer preset register). Details on
Fcarrier, high-pulse time, and low pulse time are explained as follows:
If Counter 2 source clock is FT (this clock source can set by IOC91);
FT
Fcarrier
=
2 * (1+ decimal of counter2 preset value(IOCC0)) * prescaler
If high-pulse width timer source clock is FT (this clock source can set by IOCA1);
prescaler * (1+ decimal of high pulse width timer value(IOCD0))
Thigh
=
pulse time
FT
If low-pulse width timer source clock is FT (this clock source can set by IOCA1);
prescaler * (1+ decimal of low pulse width timer value(IOCE0))
T
=
low pulse time
FT
48 •
Product Specification (V1.1) 04.11.2005
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
