Nonvolatile memory and semiconductor device with controlled voltage booster circuit

A semiconductor device incorporating therein:

• a nonvolatile memory having a plurality of nonvolatile memory elements which store data according to the magnitudes of threshold voltages thereof;
• a booster circuit which generates a voltage applied to each of the nonvolatile memory elements upon writing or erasing of the data;
• a boosted voltage detecting circuit which detects the level of the voltage boosted by the booster circuit;
• a write/erase control circuit which starts the writing or erasing based on the detection of the voltage by the boosted voltage detecting circuit;
• a write/erase end detecting circuit which detects the completion of the writing or erasing started by the write/erase control circuit;
• an end flag indicative of the completion of the writing or erasing started by the write/erase control circuit;
• a control register having control bits each indicative of an entry into an operation for the writing or erasing;
• and
• a control circuit for giving instructions as to any of the writing, erasing and reading to the nonvolatile memory according to the setting of the control bits of the control register.