Fujitsu MB91401 manual Bit data bus, Holding request withdrawal demand function OFF

MB91401					Prelminary
					2004.11.12
	• Reference Value
	Oscillation frequency	C1, C2	C3	L	Rr
	to 30 MHz	5 pF to 33 pF	None	None	None
	20 MHz to 50 MHz	5 pF to 15 pF	10 nF approx.	1 ∝H approx.	None

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.

•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.

encryption/

authentication

accelerator

MB91401

32bit

Data Bus

RAM

At the storage destination of

encryption/authentication

processing data

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.

24