Address mapping of boot transactions between dies in a system in package

摘要

An interface (52 & 56) is configured to receive transaction from a first die (2), the transaction having an address for a memory space (36a & 36b) on a second die (4). The interface (58) comprises an address translator (60) configured to translate or map the address of a first type of transaction to an address in the memory space (36a & 36b). The die further comprises boot logic to map a boot transaction to a boot region within the memory space (see Fig 3). Transactions and responses to requests are routed from the second die to the first die in the same way using an interface (56) and address translator (52) on the first die. The first die will also have its own memory space (49). The address translator may operate in selectable modes, a first mode in which translation is disabled and a second mode where translation is allowed. The translator may provide a signal to the interface indicating which mode the translator is operating in. The method and device allows a first device to boot from code in a memory on a second die and configure how the second die memory will appear to it.