11 16-BIT TIMER (T16)
S1C17001 TECHNICAL MANUAL
EPSON
109
11.2.2 External Clock Mode
External clock mode uses the clock and pulses input via the input/output port as a count clock. These inputs can
also be used as an event counter. Timer operations other than the input clock are the same as for internal clock
mode.
External clock input port
The following input ports are used for external clock or pulse input.
Table 11.2.2.1: External clock input port
Timer channel
Input signal name
Input/output port pin
Ch.0
EXCL0
P16
Ch.1
EXCL1
P07
Ch.2
EXCL2
P06
Confirm that the input/output ports used for external clock or pulse input are set to input mode (the default set-
ting). No pin function selection is needed. While the input/output ports function as general purpose inputs, the
input signal is also sent to the 16-bit timer.
The P07 and P06 ports used by 16-bit timer Ch.1 and Ch.2 incorporate chattering filter circuits and can also be
used as EXCL
x
inputs. For instructions on controlling chattering filter circuits, see “10.6 P0 Port Chattering
Filter Function.”
Signal polarity selection
CKACTV
(D10/T16_CTL
x
register) is used in this mode to select the falling edge or rising edge of the input
signal for counting.
∗
CKACTV
: External Clock Active Level Select Bit in the 16-bit Timer Ch.
x
Control (T16_CTL
x
) Register
(D10/0x4226/0x4246/0x4266)
Counting down uses the rising edge when CKACTV is 1 (default) and uses the falling edge when set to 0.
External input clock
PRUN
Counter (CKACTV = 1)
Counter (CKACTV = 0)
n-1
n-2
n-3
n-4
n-5
n-6
n-7
n-8
n-9 n-10
n
n-1
n-2
n-3
n-4
n-5
n-6
n-7
n-8
n-9 n-10
n
Figure 11.2.2.1: External clock mode count
The 16-bit timer does not use the prescaler in this mode. If no other peripheral modules use the prescaler clock, the
prescaler can be stopped to reduce current consumption. (The prescaler clock is used for P0 port chattering filter-
ing.)
Summary of Contents for S1C17001
Page 1: ...Technical Manual S1C17001 CMOS 16 BIT SINGLE CHIP MICROCONTROLLER ...
Page 33: ...4 POWER SUPPLY VOLTAGE 24 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 63: ...6 INITERRUPT CONTROLLER 54 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 87: ...8 CLOCK GENERATOR CLG 78 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 91: ...9 PRESCALER PSC 82 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 133: ...11 16 BIT TIMER T16 124 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 211: ...16 STOPWATCH TIMER SWT 202 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 219: ...17 WATCHDOG TIMER WDT 210 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 241: ...18 UART 232 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
Page 277: ...20 I2 C 268 EPSON S1C17001 TECHNICAL MANUAL This page intentionally left blank ...
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