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What items should be confirmed if initial operation doesn't go well?

Latest Updated:03/25/2009

Question:

Initial operation doesn't go well. What are the items that should be confirmed?

Answer:

First of all, please confirm the following points.

1) Is each power supply supplied correctly?

2) Is the power voltage stable?

3) Is there any problem in clock peripheral circuit?

・Please decide it after consulting enough with the oscillator maker so that the circuit constant of oscillation circuit is different depending on the stray capacity of the oscillator and mounting circuit.

4) Does not the internal clock exceed a regulated range?

The low multiplication of internal PLL circuit is decided by setting the clock mode. The internal clock such as peripheral clock, and system clock must not exceed a regulated range by this setting.

5) The reset sequence is followed?

6) Is the expected frequency output from the CK pins (system clock output pins)?

7) Is the program correctly written in on-chip ROM?

8) Are the unused pins correctly processed?

•Connect nothing to the NC pin.
•Fix the unused input pins to the high or low level.

9) Is the wait pin negated?

10) Is undefined and reserve address being accessed?

11) Even if devices are changed, is the same phenomenon generated?

Suitable Products
SH7144, SH7145
SH7065
SH7058
SH7055
SH7050, SH7051
SH7052, SH7053, SH7054
SH7047, SH7049, SH7105, SH7107, SH7109
SH7046, SH7148, SH7101, SH7048, SH7104, SH7106, SH7108
SH7040, SH7041, SH7042, SH7043, SH7044, SH7045
SH7032, SH7034, SH7034B
SH7032
SH7020, SH7021
SH7018
SH7014, SH7016, SH7017
SH7011