System on a chip appears to be the new catchword of the semiconductor industry, and implies the capability of integrating dif ferent functions on the same silicon. To this purpose, the integration of high perform ance logic and Flash memory, which pre sents several advantages, such as larger system flexibility, reduction of power dissi pation, appears very attractive. However several technological problems, mainly related to process complexity and concerns about the memory reliability, have delayed till now the introduction of this technology. In this paper we present a 0.35 JlIIl technology Flash macrocell based on a 1.8 11m2 cell and developed for embedded ap plications. After assessing the technology by processing a mask set that includes a 4Mbit test-chip and a pure logic microcon troller, a 1 Mbit Flash macrocell has been integrated and validated on a newly de signed, STlO family microcontroller.