A wakeup mechanism for computing system is disclosed. A wakeup unit connected to a host interface is configured to detect a sequence of data values and to generate the activation signal if the detected sequence matches an expected sequence of data values. First, a read by the host processor at a particular address in memory is detected by the wakeup unit. Next, a sequence of data values is written to the address by the host processor and the wakeup unit compares the sequence to an expected sequence. If there is a match, the wakeup unit causes the multitasking controller to execute a test of the data in memory. If the test is positive, then an indicator is written to the address and when the host reads the indicator, the wakeup unit causes the multitask controller to become active.