Measuring 3.6 by 2.3 by 0.5 inches, the V25-Engine/C-Engine is a C/C++ programmable microprocessor core module (5V only) with a 16-bit CPU (NEC V25). It supports up to 512 KB ROM/Flash, 512 KB battery-backed SRAM, and a 512-byte EEPROM. A real-time clock (RTC72423) provides information on the year, month, date, hour, minute, second, and 1/64 second. It also features DMA, three serial channels, three 16-bit timers, with two 16-bit counters for up to 500 kHz rising edge inputs, 24 digital I/O lines, 8 comparator inputs, five external interrupt inputs, power failure detection, watchdog timer, LED, and expansion ports. The comparator inputs can be used for either digital or analog inputs, and the comparator threshold voltage can be set in 16 steps by software.

Three serial ports are supported: V25-internal SER0 and SER1, and an optional UART (SCC2691) that supports 8-bit or 9-bit communication. The V25-internal 24 I/O lines are multifunctional and can be programmed as control, input, or output. Three 16-bit timers can provide precise timing for applications. Sample interface circuit for integrating the V25-Engine into user product is available.

The V25-Engine/C-Engine expects a regulated 5V voltage supply, and does not provide RS232 or RS485 drivers for the serial ports. The VE232 can be used to provide this.

The optional 12-bit ADC available on the C-Engine only has sample-and-hold, a high-impedance reference input, 11 single-ended 0-5V (or 0 to REF) inputs, and a 2.5 kHz sample rate.

The V25-Engine is also surface mounted, in contrast to the C-Engine which is not.

The V25-Engine/C-Engine shares a similar pin-out and physical dimensions with the i386-Engine and A-Engine.