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CHAPTER 14 FREQUENCY COUNTER
User’s Manual U15104EJ2V0UD
Figure 14-1. Block Diagram of Frequency Counter
(1) IF counter input select block
The IF counter input select block selects the pin to be used from the FMIFC and AMIFC pins, and a count
mode.
(2) Gate time control block
The gate time control block sets a gate time (count time).
(3) Start/stop control block
The start/stop control block starts counting by the IF counter register and detects the end of counting.
(4) IF counter register block
The IF counter register block is a 16-bit register that counts up the frequency input in the set gate time. The
count value is stored to the IF counter register (IFCR). When the count value reaches FFFFH, the IF counter
register holds FFFFH at the next input, and stops counting. The value of this register is reset to 0000H after
reset or in the STOP mode. In the HALT mode, it holds the current count value.
Internal bus
IFC
MD0
IFC
CK1
IFC
CK0
IFC
JG0
IF counter
mode select
register (IFCMD)
IF counter
gate judge
register (IFCJG)
IF counter
control register
(IFCCR)
IFC
MD1
IFC
RES
IFC
ST
Input select
block
Start/stop
control block
Gate time
control block
IF counter
register
(IFCR)
block
2
2
FMIFC
AMIFC