Cac Upper-Limit Value Setting Register (Caulvr); Cac Lower-Limit Value Setting Register (Callvr); Cac Counter Buffer Register (Cacntbr) - Renesas RX100 Series User Manual

RX13T Group
10.2.6

CAC Upper-Limit Value Setting Register (CAULVR)

Address(es): 0008 B006h
b15 b14
Value after reset: 0 0
CAULVR is a 16-bit readable/writable register that specifies the upper-limit value of the counter used for measuring the
frequency. When the frequency rises above the value specified in this register, a frequency error is detected.
Write to this register when the CACR0.CFME bit is 0.
The counter value held in CACNTBR can vary with the difference between the phases of the digital filter and edge-
detection circuit on the one hand and the signal on the CACREF pin on the other, so ensure that this setting allows an
adequate margin.
10.2.7

CAC Lower-Limit Value Setting Register (CALLVR)

Address(es): 0008 B008h
b15 b14
Value after reset: 0 0
CALLVR is a 16-bit readable/writable register that specifies the lower-limit value of the counter used for measuring the
frequency. When the frequency falls below the value specified in this register, a frequency error is detected.
Write to this register when the CACR0.CFME bit is 0.
The counter value held in CACNTBR can vary with the difference between the phases of the digital filter and edge-
detection circuit on the one hand and the signal on the CACREF pin on the other, so ensure that this setting allows an
adequate margin.
10.2.8

CAC Counter Buffer Register (CACNTBR)

Address(es): 0008 B00Ah
b15 b14
0 0
Value after reset:
CACNTBR is a 16-bit read-only register that retains the counter value at the time a valid reference signal edge is input.
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
b13 b12 b11 b10
0 0 0 0
b13 b12 b11 b10
0 0 0 0
b13 b12 b11 b10
0 0 0 0
10. Clock Frequency Accuracy Measurement Circuit (CAC)
b9 b8 b7 b6
0 0 0 0
b9 b8 b7 b6
0 0 0 0
b9 b8 b7 b6
0 0 0 0
b5 b4 b3 b2
0 0 0 0
b5 b4 b3 b2
0 0 0 0
b5 b4 b3 b2
0 0 0 0
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b1 b0
0 0
b1 b0
0 0
b1 b0
0 0