FUJITSU MB91401 User Manual

Page 24

MB91401

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Reference Value

It is necessary to add C3/L depending on a basic wave and the over tone characteristic of the oscillator of the
20 MHz to 30 MHz belt.

Note : These reference values are standards. The constant changes according to the characteristic of the quartz

vibrator used. Therefore, we will recommend the initial evaluation that uses the evaluation sample to the
decision of the circuit constant. Please contact FUJITSU representatives about the evaluation sample.

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Notes when encryption/authentication accelarator is used

When using the encryption/authentication installed in this LSI, it is necessary to the following notes.

32-bit data bus

The encryption/authentication accelerator fetches data from the area storing data to be subject to encryption/
authentication and encrypts or authenticates the data without CPU intervention. In the encryption processing,
write is done in the area where it wants to store the data after the encryption is processed.

Holding request withdrawal demand function OFF

When accessing to the storage destination of encryption/authentication processing data, the encryption/authen-
tication accelerator should hold an internal bus of this LSI.

Therefore, when the encryption/authentication accelerator are used, it should be set that the holding request
withdrawal doesn’t demand.

Please set the HRCL register that sets the interrupt level that becomes the standard of the holding request
withdrawal demand generation to "10000" in the FR core.

For NMIs, the hold request cancel request occurs regardless of the HRCL register setting. When the encryption/
authentication accelerator is used, therefore, NMI input may cause encryption/authentication to fail to result
correctly. In that case, the correspondence said that it will execute the encryption/authentication processing
under execution again is necessary.

Oscillation frequency

to 30 MHz

5 pF to 33 pF

None

20 MHz to 50 MHz

5 pF to 15 pF

10 nF approx.

H approx.

None

RAM

32bit

Data Bus

MB91401

encryption/

authentication

accelerator

At the storage destination of

encryption/authentication

processing data

Prelminary

2004.11.12