Toshiba TC9314F Manual page 29

Note 29: When the PLL is off, the IF counter is disabled.
(When the timer/counter is in use, the IF counter is enabled.)
(1) IF counter auto mode (frequency measuring)
To use IF counter auto mode, use the
SC bit to frequency measuring mode "0". Then, set the IF
ON
input switching bit.
Set the gate time based on the IF input frequency band. Set the MANUAL bit to "0" and the
STA/ STP bit to "1" to start the IF counter.
As a result, the clock for the 20 bit binary counter is input from the IF pin for the specified gate
time. The IF counter counts the number of input pulses. To determine when the IF counter has
finished counting, check the BUSY bit. When the count equals or exceeds 2
bit is set to "1".
To measure the frequency input to the IF input pin, load the F0~F19 IF data when the BUSY and
OVER bits are both "0".
(2) IF counter manual mode (frequency measuring)
Use manual mode to measure the frequency using the IF frequency by controlling the gate time
using an internal time base (eg, 10 Hz).
Perform the same IF counter input settings as for auto mode, and set the G0 and G1 bits to other
than "1". Set the MANUAL bit to "1" and the
STA/ STP bit to "0" terminates the count and loads the data in binary format.
(3) IF counter period mode (period measuring)
Use this mode to measure low frequencies that cannot be otherwise be measured.
The frequency is measured by inputting the reference clock (75 kHz) to the 20 bit binary counter for
one input period. Use the number of pulses to determine the period of the input.
This input pin can also be used as the IF input pin. Setting the SC
SC pin.
IN
The IF 1/ 2 bit switches between SC
frequency measurement. Set the MANUAL, G0, and G1 bits to "0".
As in frequency measuring, to start period measuring, use the BUSY bit to confirm the operation
state, then load the count data.
Note 30: When SC
IN
Note 31: Note that the BUSY bit is not cleared to "0" if no clock is input to SC
IF/ IN
and SC
IN1
input is selected, input the square wave signals DC coupled.
29
switching bit to set the IF pin to IF input, and set the
or IF
IN1 IN2
STA/ STP bit to "1" to start the count. Setting the
ON
input in the same way as for IF counter
IN2
TC9314F
pin using the IF counter
20 input pulses, the OVER
bit to "1" sets the pin as the
.
IN
2003-07-03