# 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?

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.

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 |