Z80-MBC2.Z80-MBC2 - The Next Generation: HW/SW Devlopment & Improvement. The NG HW/SW adds two SIO channels, increases the RAM to 512KB, and supports all Z80 interrupt modes IM0, IM1, IM2. The original Z80-MBC2 is an easy to build Z80 SBC (Single Board Computer), with a SD as "disk emulator" and with a 128KB banked RAM for CP/M 3 (or CP/M 2.2 or QP/M 2.71).