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Is calculation “-2.6ns” (10.4-13) which is negative value correct?

Latest Updated:04/07/2011

Question:

Under Electrical Characteristics of Bus Controller, write data setup time (tWDS1) condition is given a minimum value of "0.5 x clock cycle time (tcyc) - 13".
According to this condition, if BΦ is 48 MHz, the calculation works out to "-2.6ns" (10.4 - 13) which is a negative (-) value.
Is this correct?

Answer:

Yes, the resulting value can be negative (-).
By inserting a Th cycle using the CS assertion period control register (CSACR), write strobe setup time can be secured.
Therefore, please avoid resulting in a negative value by inserting a Th cycle.
Suitable Products
H8SX Family