20.3.3 Detection Frequency
The detection frequency have a detection frequency range and an undetectable frequency range because of
oscillation accuracy. Therefore, it is undefined whether to be detected between detection frequency range
and undetectable it.
Figure 20-2 shows the detection or undetectable frequency range when the target clock error is ±10% and
the reference clock error is ± 5%.
Subharmonic
(10MHz + 10%) ÷ 2
Detection range
Undetectable range
f
EHOSC
[MHz]
Harmonic
(10MHz - 10%) * 2
9
9.5
10
10.5
11
19.4
5.15
Figure 20-2 Example of detection frequency range (in case of 10MHz)
The higher and lower limit of the detection frequency is calculated from the maximum error of the target
clock and the reference.
How to calculate the setup value of OFDMN/OFDMX is shown below when the target clock error is
±10% and the reference clock error is ± 5%.
target clock
(f
EHOSC
)
10MHz ± 10%
Max.11MHz
-------- a
Min. 9MHz
-------- b
reference clock
(f
IHOSC
)
10MHz ± 5%
Max.10.5MHz
-------- c
Min. 9.5MHz
-------- d
higher limit of the detection frequency = 1 ÷ {(d ÷ 2
8
) ÷ (a ÷ 4)}
lower limit of the detection frequency
= 1 ÷ {(c ÷ 2
8
) ÷ (b ÷ 4)}
higher limit of the detection frequency
= 1 ÷ {(9.5 × 10
6
÷ 2
8
) ÷ (11 × 10
6
÷ 4)}
= 74.10 = 74 (truncate after the decimal places)= 0x4
A
lower limit of the detection frequency
= 1 ÷ {(10.5 × 10
6
÷ 2
8
) ÷ (9 × 10
6
÷ 4)}
= 54.85 = 55 (round up after the decimal places)= 0x37
Setting "0x4
A
" to the register OFDMX and "0x37" to the register OFDMN, when the external oscillation
of higher than 11MHz or lower than 9MHz is detected, the oscillation frequency detector outputs a reset signal.
20.3.4 Available Operation Mode
The oscillation frequency detection is available only in NORMAL and IDLE mode. Before shifting to anoth-
er mode, disable the oscillation frequency detection.
TMPM3V6/M3V4
Page 429
2019-02-06
Содержание TMPM3V4
Страница 1: ...32 Bit RISC Microcontroller TX03 Series TMPM3V6 M3V4 ...
Страница 2: ... 2019 Toshiba Electronic Devices Storage Corporation ...
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Страница 52: ...TMPM3V6 M3V4 3 Processor Core 3 6 Exclusive access Page 30 2019 02 06 ...
Страница 148: ...TMPM3V6 M3V4 7 Exceptions 7 6 Exception Interrupt Related Registers Page 126 2019 02 06 ...
Страница 178: ...TMPM3V6 M3V4 9 Input Output port 9 2 Block Diagrams of Ports Page 156 2019 02 06 ...
Страница 206: ...TMPM3V6 M3V4 10 16 bit Timer Event Counters TMRB 10 7 Applications using the Capture Function Page 184 2019 02 06 ...
Страница 232: ...TMPM3V6 M3V4 11 Universal Asynchronous Receiver Transmitter Circuit UART 11 4 Operation Description Page 210 2019 02 06 ...
Страница 354: ...TMPM3V6 M3V4 14 Synchronous Serial Port SSP 14 6 Frame Format Page 332 2019 02 06 ...
Страница 419: ...TMPM3V6 M3V4 Page 397 2019 02 06 ...
Страница 420: ...TMPM3V6 M3V4 16 Analog Digital Converter ADC 16 6 Timing chart of AD conversion Page 398 2019 02 06 ...
Страница 462: ...TMPM3V6 M3V4 21 Watchdog Timer WDT 21 5 Control register Page 440 2019 02 06 ...
Страница 510: ...TMPM3V6 M3V4 22 Flash Memory Operation 22 4 Programming in the User Boot Mode Page 488 2019 02 06 ...
Страница 538: ...TMPM3V6 M3V4 25 Electrical Characteristics 25 7 Recommended Oscillation Circuit Page 516 2019 02 06 ...
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