EM78P468LAQ EMC [ELAN Microelectronics Corp], EM78P468LAQ Datasheet - Page 51

• Manufacturer Part Number: EM78P468LAQ
• Description: 8-BIT Microcontroller
• Manufacturer: EMC [ELAN Microelectronics Corp]

Product Specification (V1.0) 03.15.2006
(This specification is subject to change without further notice)
4.10
Generate
Fm: main oscillator frequency ; Fs: sub-oscillator frequency
8 bit dow n c ounter
A uto-reload buf f er
Pre-s caler
Fs
Counter 2
Infrared Remote Control Application / PWM Waveform
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-bit down count
timer/counter, 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 F
If high-pulse width timer source clock is FT (this clock source can set by IOCA1);
If low-pulse width timer source clock is FT (this clock source can set by IOCA1);
(IOCC0)
F
(IOC91)
T
T
carrier
high
low
Fm
pulse
pulse
8
8
=
2
time
time
*
1 (
=
=
+
Pre-s caler
(IOC A 1)
prescaler
decimal
prescaler
Fcarrier
HF
Fig. 21 IR/PWM System Block Diagram
RE register
of
*
*
1 (
1 (
High-Pulse Width Timer
T
+
counter
+
(this clock source can set by IOC91);
decimal
8 bit dow n counter
A uto-reload buf f er
LGP
decimal
(IOCD0)
2
H/W Modulator Circuit
IRE
F
8
8
8
preset
of
T
of
low
high
value
F
F
T
pulse
T
pulse
(
IOCC
Low -Puls e Width Timer
8 bit dow n c ounter
A uto-reload buf f er
width
( IOCE0)
0
width
))
Pre-s caler
*
(IOCA 1)
prescaler
8
8
8
timer
8-BIT Microcontroller
timer
value
value
EM78P468L
(
IROUT pin
IOCE
(
IOCD
• 47
0
))
0
))