Microcontroller having a memory, a dedicated multitask memory, and switching circuit for selectively connecting the multitask memory to the internal or external bus

摘要

A microcontroller comprising a first memory 2 used by a CPU1 to perform arithmetic operations; a second memory 3 for a multitask process for storing data transferred from an external device 30 during the arithmetic process of CPU1; bus switches 4 and 5 for switching over the connection of data buses of CPU1 and the external device 30; and an address supply portion 7, which is connected to the address bus of the external device 30 while the second memory 3 is connected to the data bus of the external device 30, and which generates address signals by which to store data from the external device, wherein this microcontroller can perform a multitask process without adopting an expensive device such as a dual port RAM.