The Free On-line Dictionary of Computing (30 December 2018):
The successor to the Intel 8008. The 8080 had a
16-bit address bus and an 8-bit data bus. It had seven
8-bit registers (six which could also be combined as three
16-bit registers), a 16-bit stack pointer to memory which
replaced the 8008's internal stack and a 16-bit program
counter. It also had 256 I/O ports (so I/O devices could be
connected without needing to allocate any addressing space as
is required for memory mapped devices) and a signal pin that
allowed the stack to occupy a separate bank of memory.
Shortly after the 8080, the Motorola 6800 was introduced.