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An 8-bit microprocessor. The processor itselfhad no address bus - program and data memory access werecontained in separate units, which reduced the number of pinsand the associated cost. It also featured 64 registers,accessed by the ISAR register in cells (register windows) ofeight, which meant external RAM wasn't always needed forsmall applications. In addition, the 2-chip processor didn'tneed support chips, unlike others which needed seven or more.The F8 inspired other similar CPUs, such as the Intel8048. The use of the ISAR register allowed a subroutine tobe entered without saving a bunch of registers, speedingexecution - the ISAR would just be changed. Special purposeregisters were stored in the second cell (regs 9-15), and thefirst eight registers were accessed directly. The windowingconcept was useful, but only the register pointed to by theISAR could be accessed - to access other registers the ISARwas incremented or decremented through the window.