3870

Mostek

In the beginning of microprocessor production Mostek was a second source of Fairchilds F8. Both designed one-chip microcomputers around the F8. Fairchild designed the 3859, which was a simple combination of the 3850 CPU and 3851 PSU on a single chip. Mostek developed a more ambitious one-chip microcomputer, the 3870. Mostek developed this 3870 ahead of the Fairchild 3859. Therefore, Fairchild dropped the 3859 and became a second source for the 3870.

8-bit microcomputer on a single MOS integrated circuit; N-Channel ion injection silicon-gate technology; the 3870 can execute the F8 instruction set of more than 70 commands, allowing expansion into multi-chip configurations with software compatibility. The device features 2048 bytes of ROM, 64 bytes of scratchpad RAM, a programmable binary timer and interrupt, 32 bits of TTL compatible I/O and a single +5 V power supply requirement.
The 3870 has 2048bytes of mask programmable ROM; the 38E70 has 2048 bytes of UV erasable PROM

4 MHz