
Chapter 3
3.8.3 Speech Timer
There are two Speech Timers for speech Channels 1 & 2. The Speech Timers
with their interrupt functions are useful for speech/voice synthesis. You should
set the correct timer value for the desired sampling rate and implement the
synthesis algorithm in the interrupt subroutines. To control the Speech Timers
and interrupts, you have to use the control registers defined in Chapter 4,
Special Function Control
.
The Speech Timers do not have a prescaler and the clock frequency is Fosc/8.
There is a "down" counter (8-bit in width) for each Speech Timer and the reload
value is stored in the IOCC (sampling rate register). The relative interrupt is
enabled/disabled by Bit 1 (SENT) of RA. When a counter underflow occurs,
the Speech Timer interrupt will be triggered. Refer to Section 4.2,
Speech
Function Control
of Chapter 4 for more detailed description of the Speech
Timer control.
3.8.4 Watchdog Timers
The Watchdog timer (WDT) has a free running on-chip RC oscillator. It will
keep on running even if the oscillator has been turned off (i.e., switched into
Sleep Mode). During normal operation or Sleep Mode, if the WDT is enabled, a
WDT time-out forces the processor to enter a reset condition. To avoid a reset
from taking place during normal program flow, you should calculate the
program execution time and clear the WDT value by inserting a “WDTC”
instruction in the program before the WDT times out. The WDT can be enabled
or disabled by the WTE bit of the R8 register any time during the normal
operation mode.
A prescaler is also provided to generate different clock rates for the WDT clock
source. The WS0 & WS1 bits of the IOC5 register define the pre-scale ratio
ranging from 1:1 to 1:8.
EM60000 Series User’s Manual
System Control
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Содержание EM60000 series
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Страница 24: ...Chapter 2 16 Architecture EM60000 Series User s Manual ...
Страница 54: ...Chapter 4 46 Special Function Control EM60000Series User s Manual ...
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