Hitachi H8/300L Series Manual page 24

Application Perspectives
Application Example
This section describes the use of the H8/3877 Series in portable telephones. The LCD
controller/driver drives the LCD panel directly. Since the tone generators can output DTMF
signals and arbitrary tones simultaneously, the external components previously required for
optional functions, such as tone squelch, can be eliminated. This can allow overall system
costs to be significantly reduced. The built-in timers, of which there are three types, are used to
generate the basic timing for system control, for the clock and calendar functions, for the
transmission/reception control function, and for the alarm function. The two-channel serial
communication interface (SCI) is used for, e.g., radio control protocols. Finally, the A/D
converter is used for acquisition of analog data from sensors
such as the field strength sensor. Since the H8/3877 Series
provides a large capacity on-chip ROM in addition to
these powerful peripheral functions, it is possible to
implement portable telephone system control,
clock, and display control with a single
microcomputer chip.
RF amplifier
IF amplifier
Filter
Speaker
Data modem
Microphone
<Notation>
PLL:
Phase-locked loop
LCD: Liquid crystal display
H8/3877 Series
Calendar
Clock
Transmission/
reception
control
Sensor
processing
SCI
DTMF/multi-tone output
Filter
Portable telephone
LCD display I/O
Key input
DTMF
generation
Multi-tone
generation
Synchronization
Tone squelch
circuit
24
Tone Generator + LCD
LCD
Key input
Memory
Filter
Output
amplifier
PLL