86
EPSON
S1C63666 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Programmable Timer)
MOD16: 16-bit mode selection register (FFC0H•D3)
Selects whether timers 0 and 1 are used as a 16-bit timer or 2 channels of 8-bit timer.
When "1" is written: 16-bit timer
When "0" is written: 8-bit timer
Reading: Valid
When "1" is written to MOD16, a 16-bit timer is configured with timer 0 for low-order byte and timer 1 for
high-order byte. Use the timer 0 registers for control. When "0" is written to MOD16, timer 0 and timer 1
are used as independent 8-bit timers.
At initial reset, this register is set to "0".
EVCNT: Timer 0 counter mode selection register (FFC0H•D2)
Selects a counter mode for timer 0.
When "1" is written: Event counter mode
When "0" is written: Timer mode
Reading: Valid
The counter mode for timer 0 is selected from either the event counter mode or timer mode. When "1" is
written to the EVCNT register, the event counter mode is selected and when "0" is written, the timer
mode is selected.
At initial reset, this register is set to "0".
FCSEL: Timer 0 function selection register (FFC0H•D1)
Selects whether the noise rejector of the clock input circuit will be used or not in the event counter mode.
When "1" is written: With noise rejector
When "0" is written: Without noise rejector
Reading: Valid
When "1" is written to the FCSEL register, the noise rejector is used and counting is done by an external
clock (K13) with 0.98 msec
*
or more pulse width. The noise rejector allows the counter to input the clock
at the second falling edge of the internal 2,048 Hz
*
signal after changing the input level of the K13 input
port terminal. Consequently, the pulse width of noise that can reliably be rejected is 0.48 msec
*
or less.
(
∗
: f
OSC1
= 32.768 kHz)
When "0" is written to the FCSEL register, the noise rejector is not used and the counting is done directly
by an external clock input to the K13 input port terminal.
Setting of this register is effective only when timer 0 is used in the event counter mode.
At initial reset, this register is set to "0".
PLPOL: Timer 0 pulse polarity selection register (FFC0H•D0)
Selects the count pulse polarity in the event counter mode.
When "1" is written: Rising edge
When "0" is written: Falling edge
Reading: Valid
The count timing in the event counter mode (timer 0) is selected from either the falling edge of the
external clock input to the K13 input port terminal or the rising edge. When "0" is written to the PLPOL
register, the falling edge is selected and when "1" is written, the rising edge is selected.
Setting of this register is effective only when timer 0 is used in the event counter mode.
At initial reset, this register is set to "0".
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