SPLIT MEMORY TYPE SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PURPOSE:To attain the quick return to an external memory mode without any input of an external reset signal by providing an operation mode switching circuit which is controlled based on an A/D conversion end signal during discontinuation of the CPU function and switches a CPU function stop mode to an external program mode. CONSTITUTION:An operation mode switching circuit control part 5b controls an operation mode switching circuit 5 to select an external program memory 3 and sets an external memory mode. A CPU 1 sets a conversion mode setting register 7b and starts the A/D conversion of an A/D converting circuit 7. Then the CPU 1 carried out a CPU function stop instruction in the external memory mode and selects a CPU function stop mode via the part 5b. When the A/D conversion ends, the part 5b returns the operation mode to the external memory mode from the CPU function stop mode.