User's Manual

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 219 of 1852
Nov 30, 2020
RX23W Group 10. Clock Frequency Accuracy Measurement Circuit (CAC)
Figure 10.1 CAC Block Diagram
Table 10.2 shows the pin configuration of the CAC.
Table 10.2 Pin Configuration of CAC
Pin Name I/O Function
CACREF Input Measurement reference clock input pin
Measurement
target clock
select circuit
Measurement
reference
clock select
circuit
Frequency
dividing circuit
Frequency
dividing circuit
IWDTCLK
LOCO clock
HOCO clock
Sub-clock
Main clock
1/4
1/8
1/32
16-bit counter
Comparator
CAULVR
1/128
1/1024
1/8192
Edge detection
circuit
CACREF
CACREFE
RSCS[2:0] RCDS[1:0]
FMCS[2:0]
TCSS[1:0]
EDGES[1:0]
CFME
Count source
clock
Valid edge signal
Frequency error interrupt
request
Internal peripheral bus
RPS
1/32
CACNTBR
CALLVR
Measurement end interrupt
request
Overflow interrupt request
CAICR CASTR
Interrupt control
circuit
Digital filter
DFS[1:0]
Measurement
target clock
DFS[1:0]
PCLKB
CFME: Bit in CACR0
CACREFE, FMCS[2:0], TCSS[1:0], EDGES[1:0]: Bits in CACR1
RPS, RSCS[2:0], RCDS[1:0], DFS[1:0]: Bits in CACR2
CAICR: CAC interrupt control register
CASTR: CAC status register
CAULVR: CAC upper-limit value setting register
CALLVR: CAC lower-limit value setting register
CACNTBR: CAC counter buffer register