USE OF INTERNAL MEMORY AND EXTERNAL MEMORY

摘要

PROBLEM TO BE SOLVED: To provide a circuit and a method which allows all of internal memories and external memories that a microcontroller can use to be selected and also enable access to those memories at low cost with reliability. SOLUTION: A command from the microcontroller 10 consisting of a CPU 12, an internal memory ROM 14, etc., is received on the input 48 of a circuit 30 including a logic circuit and this command gives a selective indication to the circuit 30 to reset the microcontroller 10, which is instructed to gain access to an internal memory as a base memory and access even an external memory 18. The logic circuit sends an internal base memory select signal out selectively through a memory selection output 32 and also sends an external base memory select signal out selectively while a reset signal is processed by the microcontroller 10.